Special Report
Statistics in Medicine — Reporting of Subgroup Analyses in Clinical Trials
N Engl J Med 2007; 357:2189-2194November 22, 2007
- Article
Medical research relies on clinical trials to assess therapeutic benefits. Because of the effort and cost involved in these studies, investigators frequently use analyses of subgroups of study participants to extract as much information as possible. Such analyses, which assess the heterogeneity of treatment effects in subgroups of patients, may provide useful information for the care of patients and for future research. However, subgroup analyses also introduce analytic challenges and can lead to overstated and misleading results.1-7 This report outlines the challenges associated with conducting and reporting subgroup analyses, and it sets forth guidelines for their use in the Journal. Although this report focuses on the reporting of clinical trials, many of the issues discussed also apply to observational studies.
Subgroup Analyses and Related Concepts
Subgroup Analysis
By “subgroup analysis,” we mean any evaluation of treatment effects for a specific end point in subgroups of patients defined by baseline characteristics. The end point may be a measure of treatment efficacy or safety. For a given end point, the treatment effect — a comparison between the treatment groups — is typically measured by a relative risk, odds ratio, or arithmetic difference. The research question usually posed is this: Do the treatment effects vary among the levels of a baseline factor?
A subgroup analysis is sometimes undertaken to assess treatment effects for a specific patient characteristic; this assessment is often listed as a primary or secondary study objective. For example, Sacks et al.8 conducted a placebo-controlled trial in which the reduction in the incidence of coronary events with the use of pravastatin was examined in a diverse population of persons who had survived a myocardial infarction. In subgroup analyses, the investigators further examined whether the efficacy of pravastatin relative to placebo in preventing coronary events varied according to the patients' baseline low-density lipoprotein (LDL) levels.
Subgroup analyses are also undertaken to investigate the consistency of the trial conclusions among different subpopulations defined by each of multiple baseline characteristics of the patients. For example, Jackson et al.9 reported the outcomes of a study in which 36,282 postmenopausal women 50 to 79 years of age were randomly assigned to receive 1000 mg of elemental calcium with 400 IU of vitamin D3 daily or placebo. Fractures, the primary outcome, were ascertained over an average follow-up period of 7.0 years; bone density was a secondary outcome. Overall, no treatment effect was found for the primary outcome; that is, the active treatment was not shown to prevent fractures. The effect of calcium plus vitamin D supplementation relative to placebo on the risk of each of four fracture outcomes was further analyzed for consistency in subgroups defined by 15 characteristics of the participants.
Heterogeneity and Statistical Interactions
The heterogeneity of treatment effects across the levels of a baseline variable refers to the circumstance in which the treatment effects vary across the levels of the baseline characteristic. Heterogeneity is sometimes further classified as being either quantitative or qualitative. In the first case, one treatment is always better than the other, but by various degrees, whereas in the second case, one treatment is better than the other for one subgroup of patients and worse than the other for another subgroup of patients. Such variation, also called “effect modification,” is typically expressed in a statistical model as an interaction term or terms between the treatment group and the baseline variable. The presence or absence of interaction is specific to the measure of the treatment effect.
The appropriate statistical method for assessing the heterogeneity of treatment effects among the levels of a baseline variable begins with a statistical test for interaction.10-13 For example, Sacks et al.8 showed the heterogeneity in pravastatin efficacy by reporting a statistically significant (P=0.03) result of testing for the interaction between the treatment and baseline LDL level when the measure of the treatment effect was the relative risk. Many trials lack the power to detect heterogeneity in treatment effect; thus, the inability to find significant interactions does not show that the treatment effect seen overall necessarily applies to all subjects. A common mistake is to claim heterogeneity on the basis of separate tests of treatment effects within each of the levels of the baseline variable.6,7,14 For example, testing the hypothesis that there is no treatment effect in women and then testing it separately in men does not address the question of whether treatment differences vary according to sex. Another common error is to claim heterogeneity on the basis of the observed treatment-effect sizes within each subgroup, ignoring the uncertainty of these estimates.
Multiplicity
It is common practice to conduct a subgroup analysis for each of several — and often many — baseline characteristics, for each of several end points, or for both. For example, the analysis by Jackson and colleagues9 of the effect of calcium plus vitamin D supplementation relative to placebo on the risk of each of four fracture outcomes for 15 participant characteristics resulted in a total of 60 subgroup analyses.
When multiple subgroup analyses are performed, the probability of a false positive finding can be substantial.7 For example, if the null hypothesis is true for each of 10 independent tests for interaction at the 0.05 significance level, the chance of at least one false positive result exceeds 40%. Thus, one must be cautious in the interpretation of such results. There are several methods for addressing multiplicity that are based on the use of more stringent criteria for statistical significance than the customary P<0.05.7,15 A less formal approach for addressing multiplicity is to note the number of nominally significant interaction tests that would be expected to occur by chance alone. For example, after noting that 60 subgroup analyses were planned, Jackson et al.9 pointed out that “Up to three statistically significant interaction tests (P<0.05) would be expected on the basis of chance alone,” and then they incorporated this consideration in their interpretation of the results.
Prespecified Analysis versus Post Hoc Analysis
A prespecified subgroup analysis is one that is planned and documented before any examination of the data, preferably in the study protocol. This analysis includes specification of the end point, the baseline characteristic, and the statistical method used to test for an interaction. For example, the Heart Outcomes Prevention Evaluation 2 investigators16 conducted a study involving 5522 patients with vascular disease or diabetes to assess the effect of homocysteine lowering with folic acid and B vitamins on the risk of a major cardiovascular event. The primary outcome was a composite of death from cardiovascular causes, myocardial infarction, and stroke. In the Methods section of their article, the authors noted that “Prespecified subgroup analyses involving Cox models were used to evaluate outcomes in patients from regions with folate fortification of food and regions without folate fortification, according to the baseline plasma homocysteine level and the baseline serum creatinine level.” Post hoc analyses refer to those in which the hypotheses being tested are not specified before any examination of the data. Such analyses are of particular concern because it is often unclear how many were undertaken and whether some were motivated by inspection of the data. However, both prespecified and post hoc subgroup analyses are subject to inflated false positive rates arising from multiple testing. Investigators should avoid the tendency to prespecify many subgroup analyses in the mistaken belief that these analyses are free of the multiplicity problem.
Subgroup Analyses in the Journal — Assessment of Reporting Practices
As part of internal quality-control activities at the Journal, we assessed the completeness and quality of subgroup analyses reported in the Journal during the period from July 1, 2005, through June 30, 2006. A detailed description of the study methods can be found in the Supplementary Appendix, available with the full text of this article at www.nejm.org. In this report, we describe the clarity and completeness of subgroup-analysis reporting, evaluate the authors' interpretation and justification of the results of subgroup analyses, and recommend guidelines for reporting subgroup analyses.
Among the original articles published in the Journal during the period from July 1, 2005, through June 30, 2006, a total of 95 articles reported primary outcome results from randomized clinical trials. Among these 95 articles, 93 reported results from one clinical trial; the remaining 2 articles reported results from two trials. Thus, results from 97 trials were reported, from which subgroup analyses were reported for 59 trials (61%). Table 1Table 1
Characteristics and Predictors of Reporting Subgroup Analyses in 97 Clinical Trials. summarizes the characteristics of the trials. We found that larger trials and multicenter trials were significantly more likely to report subgroup analyses than smaller trials and single-center trials, respectively. With the use of multivariate logistic-regression models, when ranked according to the number of participants enrolled in a trial and compared with trials with the fewest participants, the odds ratio for reporting subgroup analyses for the second quartile was 1.38 (95% confidence interval [CI], 0.45 to 4.20), for the third quartile was 1.98 (95% CI, 0.62 to 6.24), and for the fourth quartile was 8.90 (95% CI, 2.10 to 37.78) (P=0.02, trend test). The odds ratio for reporting subgroup analyses in multicenter trials as compared with single-center trials was 4.33 (95% CI, 1.56 to 12.16).Among the 59 trials that reported subgroup analyses, these analyses were mentioned in the Methods section for 21 trials (36%), in the Results section for 57 trials (97%), and in the Discussion section for 37 trials (63%); subgroup analyses were reported in both the text and a figure or table for 39 trials (66%). Other characteristics of the reports are shown in Figure 1Figure 1
Reporting of Subgroup Analyses from 59 Clinical Trials.. In general, we are unable to determine the number of subgroup analyses conducted; we attempted to count the number of subgroup analyses reported in the article and found that this number was unclear in nine articles (15%). For example, Lees et al.17 reported that “We explored analyses of numerous other subgroups to assess the effect of baseline prognostic factors or coexisting conditions on the treatment effect but found no evidence of nominal significance for any biologically likely factor.” For four of these nine articles, we were able to determine that at least eight subgroup analyses were reported. In 40 trials (68%), it was unclear whether any of the subgroup analyses were prespecified or post hoc, and in 3 others (5%) it was unclear whether some were prespecified or post hoc. Interaction tests were reported to have been used to assess the heterogeneity of treatment effects for all subgroup analyses in only 16 trials (27%), and they were reported to be used for some, but not all, subgroup analyses in 11 trials (19%).We assessed whether information was provided about treatment effects within the levels of each subgroup variable (Figure 1). In 25 trials (42%), information about treatment effects was reported consistently for all of the reported subgroup analyses, and in 13 trials (22%), nothing was reported. Investigators in 15 trials (25%), all using superiority designs,10 claimed heterogeneity of treatment effects between at least one subject subgroup and the overall study population (see Table 1 of the Supplementary Appendix). For 4 of these 15 trials, this claim was based on a nominally significant interaction test, and for 4 others it was based on within-subgroup comparisons only. In the remaining seven trials, significant results of interaction tests were reported for some but not all subgroup analyses. When heterogeneity in the treatment effect was reported, for two trials (13%), investigators offered caution about multiplicity, and for four trials (27%), investigators noted the heterogeneity in the Abstract section.
Analysis of Our Findings and Guidelines for Reporting Subgroups
In the 1-year period studied, the reporting of subgroup analyses was neither uniform nor complete. Because the design of future clinical trials can depend on the results of subgroup analyses, uniformity in reporting would strengthen the foundation on which such research is built. Furthermore, uniformity of reporting will be of value in the interval between recognition of a potential subgroup effect and the availability of adequate data on which to base clinical decisions.
Problems in the reporting of subgroup analyses are not new.1-6,18 Assmann et al.2 reported shortcomings of subgroup analyses in a review of the results of 50 trials published in 1997 in four leading medical journals. More recently, Hernández et al.4 reviewed the results of 63 cardiovascular trials published in 2002 and 2004 and noted the same problems. To improve the quality of reports of parallel-group randomized trials, the Consolidated Standards of Reporting Trials statement was proposed in the mid-1990s and revised in 2001.19 Although there has been considerable discussion of the potential problems associated with subgroup analysis and recommendations on when and how subgroup analyses should be conducted and reported,19,20 our analysis of recent articles shows that problems and ambiguities persist in articles published in the Journal. For example, we found that in about two thirds of the published trials, it was unclear whether any of the reported subgroup analyses were prespecified or post hoc. In more than half of the trials, it was unclear whether interaction tests were used, and in about one third of the trials, within-level results were not presented in a consistent way.
When properly planned, reported, and interpreted, subgroup analyses can provide valuable information. With the availability of Web supplements, the opportunity exists to present more detailed information about the results of a trial. The purpose of the guidelines (see Guidelines for Reporting Subgroup Analysis) is to encourage more clear and complete reporting of subgroup analyses. In some settings, a trial is conducted with a subgroup analysis as one of the primary objectives. These guidelines are directly applicable to the reporting of subgroup analyses in the primary publication of a clinical trial when the subgroup analyses are not among the primary objectives. In other settings, including observational studies, we encourage complete and thorough reporting of the subgroup analyses in the spirit of the guidelines listed.
Guidelines for Reporting Subgroup Analysis
In the Abstract:
Present subgroup results in the Abstract only if the subgroup analyses were based on a primary study outcome, if they were prespecified, and if they were interpreted in light of the totality of prespecified subgroup analyses undertaken.
In the Methods section:
Indicate the number of prespecified subgroup analyses that were performed and the number of prespecified subgroup analyses that are reported. Distinguish a specific subgroup analysis of special interest, such as that in the article by Sacks et al.,8 from the multiple subgroup analyses typically done to assess the consistency of a treatment effect among various patient characteristics, such as those in the article by Jackson et al.9 For each reported analysis, indicate the end point that was assessed and the statistical method that was used to assess the heterogeneity of treatment differences.
Indicate the number of post hoc subgroup analyses that were performed and the number of post hoc subgroup analyses that are reported. For each reported analysis, indicate the end point that was assessed and the statistical method used to assess the heterogeneity of treatment differences. Detailed descriptions may require a supplementary appendix.
Indicate the potential effect on type I errors (false positives) due to multiple subgroup analyses and how this effect is addressed. If formal adjustments for multiplicity were used, describe them; if no formal adjustment was made, indicate the magnitude of the problem informally, as done by Jackson et al.9
In the Results section:
When possible, base analyses of the heterogeneity of treatment effects on tests for interaction, and present them along with effect estimates (including confidence intervals) within each level of each baseline covariate analyzed. A forest plot21,22 is an effective method for presenting this information.
In the Discussion section:
Avoid overinterpretation of subgroup differences. Be properly cautious in appraising their credibility, acknowledge the limitations, and provide supporting or contradictory data from other studies, if any.
The editors and statistical consultants of the Journal consider these guidelines to be important in the reporting of subgroup analyses. The goal is to provide transparency in the statistical methods used in order to increase the clarity and completeness of the information reported. As always, these are guidelines and not rules; additions and exemptions can be made as long as there is a clear case for such action.
No potential conflict of interest relevant to this article was reported.
We thank Doug Altman, John Bailar, Colin Begg, Mohan Beltangady, Marc Buyse, David DeMets, Stephen Evans, Thomas Fleming, David Harrington, Joe Heyse, David Hoaglin, Michael Hughes, John Ioannidis, Curtis Meinert, James Neaton, Robert O'Neill, Ross Prentice, Stuart Pocock, Robert Temple, Janet Wittes, and Marvin Zelen for their helpful comments.
- References
References
1
Yusuf S ,Wittes J ,Probstfield J ,Tyroler HA . Analysis and interpretation of treatment effects in subgroups of patients in randomized clinical trials. JAMA 1991;266:93-98
CrossRef | Web of Science | Medline2
Assmann SF ,Pocock SJ ,Enos LE ,Kasten LE . Subgroup analysis and other (mis)uses of baseline data in clinical trials. Lancet 2000;355:1064-1069
CrossRef | Web of Science | Medline3
Pocock SJ ,Assmann SF ,Enos LE ,Kasten LE . Subgroup analysis, covariate adjustment and baseline comparisons in clinical trial reporting: current practice and problems. Stat Med 2002;21:2917-2930
CrossRef | Web of Science | Medline4
Hernandez A ,Boersma E ,Murray G ,Habbema J ,Steyerberg E . Subgroup analyses in therapeutic cardiovascular clinical trials: are most of them misleading? Am Heart J 2006;151:257-264
CrossRef | Web of Science | Medline5
Parker AB ,Naylor CD . Subgroups, treatment effects, and baseline risks: some lessons from major cardiovascular trials. Am Heart J 2000;139:952-961
CrossRef | Web of Science | Medline6
Rothwell PM . Subgroup analysis in randomised controlled trials: importance, indications, and interpretation. Lancet 2005;365:176-186
CrossRef | Web of Science | Medline7
Lagakos SW . The challenge of subgroup analyses -- reporting without distorting. N Engl J Med 2006;354:1667-1669[Erratum, N Engl J Med 2006;355:533.]
Full Text | Web of Science | Medline8
Sacks FM ,Pfeffer MA ,Moye LA , et al. The effect of pravastatin on coronary events after myocardial infarction in patients with average cholesterol levels. N Engl J Med 1996;335:1001-1009
Full Text | Web of Science | Medline9
Jackson RD ,LaCroix AZ ,Gass M , et al. Calcium plus vitamin D supplementation and the risk of fractures. N Engl J Med 2006;354:669-683[Erratum, N Engl J Med 2006;354:1102.]
Full Text | Web of Science | Medline10
Pocock SJ. Clinical trials: a practical approach. Chichester, England: John Wiley, 1983.
11
Halperin M ,Ware JH ,Byar DP , et al. Testing for interaction in an I×J×K contingency table. Biometrika 1977;64:271-275
Web of Science12
Simon R . Patient subsets and variation in therapeutic efficacy. Br J Clin Pharmacol 1982;14:473-482
Web of Science | Medline13
Gail M ,Simon R . Testing for qualitative interactions between treatment effects and patient subsets. Biometrics 1985;41:361-372
CrossRef | Web of Science | Medline14
Brookes ST ,Whitely E ,Egger M ,Smith GD ,Mulheran PA ,Peters T . Subgroup analyses in randomized trials: risks of subgroup-specific analyses; power and sample size for the interaction test. J Clin Epidemiol 2004;57:229-236
CrossRef | Web of Science | Medline15
Bailar JC III, Mosteller F, eds. Medical uses of statistics. 2nd ed. Waltham, MA: NEJM Books, 1992.
16
Lonn E ,Yusuf S ,Arnold MJ , et al. Homocysteine lowering with folic acid and B vitamins in vascular disease. N Engl J Med 2006;354:1567-1577[Erratum, N Engl J Med 2006;355:746.]
Full Text | Web of Science | Medline17
Lees KR ,Zivin JA ,Ashwood T , et al. NXY-059 for acute ischemic stroke. N Engl J Med 2006;354:588-600
Full Text | Web of Science | Medline18
Al-Marzouki S ,Roberts I ,Marshall T ,Evans S . The effect of scientific misconduct on the results of clinical trials: a Delphi survey. Contemp Clin Trials 2005;26:331-337
CrossRef | Web of Science | Medline19
Moher D, Schulz KF, Altman DG, et al. The CONSORT Statement: revised recommendations for improving the quality of reports of parallel-group randomized trials. (Accessed November 1, 2007, at http://www.consort-statement.org/.)
20
International Conference on Harmonisation (ICH). Guidance for industry: E9 statistical principles for clinical trials. Rockville, MD: Food and Drug Administration, September 1998. (Accessed November 1, 2007, at http://www.fda.gov/cder/guidance/ICH_E9-fnl.PDF.)
21
Cuzick J . Forest plots and the interpretation of subgroups. Lancet 2005;365:1308-1308
CrossRef | Web of Science | Medline22
Wactawski-Wende J ,Kotchen JM ,Anderson GL , et al. Calcium plus vitamin D supplementation and the risk of colorectal cancer. N Engl J Med 2006;354:684-696
Full Text | Web of Science | Medline
- Citing Articles (152)
Citing Articles
1
Matthias Huber, Andras Treszl, Markus Wehland, Ingke Winther, Irina Zergibel, Rona Reibis, Juliane Bolbrinker, Monika Stoll, Gilbert Schönfelder, Karl Wegscheider, Heinz Völler, Reinhold Kreutz. (2012) Genetic variants implicated in telomere length associated with left ventricular function in patients with hypertension and cardiac organ damage. Journal of Molecular Medicine
CrossRef2
V. A. Triant, F. Josephson, C. G. Rochester, K. N. Althoff, K. Marcus, R. Munk, C. Cooper, R. B. D'Agostino, D. Costagliola, C. A. Sabin, P. L. Williams, S. Hughes, W. S. Post, N. Chandra-Strobos, G. Guaraldi, S. S. Young, R. Obenchain, R. Bedimo, V. Miller, J. Strobos. (2012) Adverse Outcome Analyses of Observational Data: Assessing Cardiovascular Risk in HIV Disease. Clinical Infectious Diseases 54:3, 408-413
CrossRef3
Michael R McClung, Steven Boonen, Ove Törring, Christian Roux, René Rizzoli, Henry G Bone, Claude-Laurent Benhamou, Willem F Lems, Salvatore Minisola, Johan Halse, Hans C Hoeck, Richard Eastell, Andrea Wang, Suresh Siddhanti, Steven R Cummings. (2012) Effect of denosumab treatment on the risk of fractures in subgroups of women with postmenopausal osteoporosis. Journal of Bone and Mineral Research 27:1, 211-218
CrossRef4
Jeannette Painovich, Patricia M. Herman. (2012) Acupuncture in the Inpatient Acute Care Setting: A Pragmatic, Randomized Control Trial. Evidence-Based Complementary and Alternative Medicine 2012, 1-8
CrossRef5
Lemuel A. Moyé. (2012) Rudiments of Subgroup Analyses. Progress in Cardiovascular Diseases 54:4, 338-342
CrossRef6
Nasir Umar, David Litaker, Marthe-Lisa Schaarschmidt, Wiebke K Peitsch, Astrid Schmieder, Darcey D Terris. (2012) Outcomes Associated with Matching Patients' Treatment Preferences to Physicians' Recommendations: Study Methodology. BMC Health Services Research 12:1, 1
CrossRef7
Ricci Harris, Donna Cormack, Martin Tobias, Li-Chia Yeh, Natalie Talamaivao, Joanna Minster, Roimata Timutimu. (2011) The pervasive effects of racism: Experiences of racial discrimination in New Zealand over time and associations with multiple health domains. Social Science & Medicine
CrossRef8
Francesco Merli, Stefano Luminari, Giuseppe Rossi, Caterina Mammi, Luigi Marcheselli, Alessandra Tucci, Fiorella Ilariucci, Annalisa Chiappella, Maurizio Musso, Alice Di Rocco, Caterina Stelitano, Isabel Alvarez, Luca Baldini, Patrizio Mazza, Flavia Salvi, Annalisa Arcari, Alberto Fragasso, Paolo G. Gobbi, Anna Marina Liberati, Massimo Federico. (2011) Cyclophosphamide, doxorubicin, vincristine, prednisone and rituximab versus epirubicin, cyclophosphamide, vinblastine, prednisone and rituximab for the initial treatment of elderly “fit” patients with diffuse large B-cell lymphoma: results from the ANZINTER3 trial of the Intergruppo Italiano Linfomi. Leukemia & Lymphoma1-8
CrossRef9
Marie-Ange Paget, Christy ChuangStein, Christine Fletcher, Carol Reid. (2011) Subgroup analyses of clinical effectiveness to support health technology assessments. Pharmaceutical Statistics 10:6, 532-538
CrossRef10
Jared C. Foster, Jeremy M.G. Taylor, Stephen J. Ruberg. (2011) Subgroup identification from randomized clinical trial data. Statistics in Medicine 30:24, 2867-2880
CrossRef11
Andrew P. White, Paul M. Arnold, Daniel C. Norvell, Erika Ecker, Michael G. Fehlings. (2011) Pharmacologic Management of Chronic Low Back Pain. Spine 36, S131-S143
CrossRef12
Thomas E. Mroz, Daniel C. Norvell, Erika Ecker, Marcelo Gruenberg, Andrew Dailey, Darrel S. Brodke. (2011) Fusion Versus Nonoperative Management for Chronic Low Back Pain. Spine 36, S75-S86
CrossRef13
Theodore J. Choma, James M. Schuster, Daniel C. Norvell, Joseph R. Dettori, Norman B. Chutkan. (2011) Fusion Versus Nonoperative Management for Chronic Low Back Pain. Spine 36, S87-S95
CrossRef14
K. C. Siontis, E. Evangelou, J. P. Ioannidis. (2011) Magnitude of effects in clinical trials published in high-impact general medical journals. International Journal of Epidemiology 40:5, 1280-1291
CrossRef15
John H. Kempen, Michael M. Altaweel, Janet T. Holbrook, Douglas A. Jabs, Thomas A. Louis, Elizabeth A. Sugar, Jennifer E. Thorne. (2011) Randomized Comparison of Systemic Anti-inflammatory Therapy Versus Fluocinolone Acetonide Implant for Intermediate, Posterior, and Panuveitis: The Multicenter Uveitis Steroid Treatment Trial. Ophthalmology 118:10, 1916-1926
CrossRef16
Daryl R. Fourney, Gunnar Andersson, Paul M. Arnold, Joseph Dettori, Alex Cahana, Michael G. Fehlings, Dan Norvell, Dino Samartzis, Jens R. Chapman. (2011) Chronic Low Back Pain. Spine 36, S1-S9
CrossRef17
Michael D. Daubs, Daniel C. Norvell, Robert McGuire, Robert Molinari, Jeffrey T. Hermsmeyer, Daryl R. Fourney, J. P. Wolinsky, Darrel Brodke. (2011) Fusion Versus Nonoperative Care for Chronic Low Back Pain. Spine 36, S96-S109
CrossRef18
Dennis Gorman. (2011) Does the Life Skills Training program reduce use of marijuana?. Addiction Research & Theory 19:5, 470-481
CrossRef19
Corren, Jonathan, Lemanske, Robert F. Jr., Hanania, Nicola A., Korenblat, Phillip E., Parsey, Merdad V., Arron, Joseph R., Harris, Jeffrey M., Scheerens, Heleen, Wu, Lawren C., Su, Zheng, Mosesova, Sofia, Eisner, Mark D., Bohen, Sean P., Matthews, John G., . (2011) Lebrikizumab Treatment in Adults with Asthma. New England Journal of Medicine 365:12, 1088-1098
Full Text20
Oliver Karam, Marisa Tucci, Thierry Ducruet, Heather Anne Hume, Jacques Lacroix, France Gauvin. (2011) Red blood cell transfusion thresholds in pediatric patients with sepsis*. Pediatric Critical Care Medicine 12:5, 512-518
CrossRef21
Kallappa M. Koti. (2011) Exponential Failure-Time Mixture Model Approach for Validating KRAS as a Predictive Biomarker for Panitumumab Monotherapy in the Treatment of Metastatic Colorectal Cancer. Statistics in Biopharmaceutical Research 3:3, 425-433
CrossRef22
Despina G. Contopoulos-Ioannidis, John P. A. Ioannidis. (2011) Claims for improved survival from systemic corticosteroids in diverse conditions: an umbrella review. European Journal of Clinical Investigationno-no
CrossRef23
Yasuhiro Usui, Yoshifumi Takata, Yuichi Inoue, Katsunori Shimada, Hirofumi Tomiyama, Yosuke Nishihata, Kota Kato, Kazuki Shiina, Akira Yamashina. (2011) Coexistence of obstructive sleep apnoea and metabolic syndrome is independently associated with left ventricular hypertrophy and diastolic dysfunction. Sleep and Breathing
CrossRef24
C. W. B. Boonacker, A. W. Hoes, K. van Liere-Visser, A. G. M. Schilder, M. M. Rovers. (2011) A Comparison of Subgroup Analyses in Grant Applications and Publications. American Journal of Epidemiology 174:2, 219-225
CrossRef25
Keyur Patel, Alexander J Thompson, Wan-Long Chuang, Chuan-Mo Lee, Chen-Yuan Peng, Ganesananthan Shanmuganathan, Satawat Thongsawat, Tawesak Tanwandee, Varocha Mahachai, Chutima Pramoolsinsap, Mong Cho, Kwang Hyup Han, Samir R Shah, Graham R Foster, Paul J Clark, Erik Pulkstenis, G. Mani Subramanian, John G McHutchison. (2011) Insulin resistance is independently associated with significant hepatic fibrosis in Asian chronic hepatitis C genotype 2 or 3 patients. Journal of Gastroenterology and Hepatology 26:7, 1182-1188
CrossRef26
Charles D. Scales, Steven E. Canfield. (2011) Advanced topics in evidence-based urological oncology: Using results of a subgroup analysis. Urologic Oncology: Seminars and Original Investigations 29:4, 462-466
CrossRef27
Donna M. Zulman, Jeremy B. Sussman, Xisui Chen, Christine T. Cigolle, Caroline S. Blaum, Rodney A. Hayward. (2011) Examining the Evidence: A Systematic Review of the Inclusion and Analysis of Older Adults in Randomized Controlled Trials. Journal of General Internal Medicine 26:7, 783-790
CrossRef28
Amna Turky, David Felce, Glyn Jones, Mike Kerr. (2011) A prospective case control study of psychiatric disorders in adults with epilepsy and intellectual disability. Epilepsia 52:7, 1223-1230
CrossRef29
Barbara-Ann Adelstein, Timothy A. Dobbins, Carole A. Harris, Ian C. Marschner, Robyn L. Ward. (2011) A systematic review and meta-analysis of KRAS status as the determinant of response to anti-EGFR antibodies and the impact of partner chemotherapy in metastatic colorectal cancer. European Journal of Cancer 47:9, 1343-1354
CrossRef30
Rui Wang, James H. Ware. (2011) Detecting Moderator Effects Using Subgroup Analyses. Prevention Science
CrossRef31
Park, Seung-Jung, Kim, Young-Hak, Park, Duk-Woo, Yun, Sung-Cheol, Ahn, Jung-Min, Song, Hae Geun, Lee, Jong-Young, Kim, Won-Jang, Kang, Soo-Jin, Lee, Seung-Whan, Lee, Cheol Whan, Park, Seong-Wook, Chung, Cheol-Hyun, Lee, Jae-Won, Lim, Do-Sun, Rha, Seung-Woon, Lee, Sang-Gon, Gwon, Hyeon-Cheol, Kim, Hyo-Soo, Chae, In-Ho, Jang, Yangsoo, Jeong, Myung-Ho, Tahk, Seung-Jea, Seung, Ki Bae, . (2011) Randomized Trial of Stents versus Bypass Surgery for Left Main Coronary Artery Disease. New England Journal of Medicine 364:18, 1718-1727
Full Text32
J.-B. Ricco, G. Régnault de la Mothe, S. Fujita, O. Page, A. Valagier, C. Marchand. (2011) Impact of Routine Completion Angiography on the Results of Primary Carotid Endarterectomy: A Prospective Study in a Teaching Hospital. European Journal of Vascular and Endovascular Surgery 41:5, 579-588
CrossRef33
Desmond M. Ryan, Robert J. Lupinacci, Nicholas A. Kartsonis. (2011) Efficacy and safety of caspofungin in obese patients. Medical Mycology1-7
CrossRef34
Mirjam J. Knol, Wiebe R. Pestman, Diederick E. Grobbee. (2011) The (mis)use of overlap of confidence intervals to assess effect modification. European Journal of Epidemiology 26:4, 253-254
CrossRef35
Kenya Yamanaka, Etsuro Hatano, Masato Narita, Kojiro Taura, Kentaro Yasuchika, Takashi Nitta, Shigeki Arizono, Hiroyoshi Isoda, Toshiya Shibata, Iwao Ikai, Tosiya Sato, Shinji Uemoto. (2011) Comparative study of cisplatin and epirubicin in transcatheter arterial chemoembolization for hepatocellular carcinoma. Hepatology Research 41:4, 303-309
CrossRef36
L. Zeng, H. Yan, Y. Cheng, M. J. Dibley. (2011) Modifying effects of wealth on the response to nutrient supplementation in pregnancy on birth weight, duration of gestation and perinatal mortality in rural western China: double-blind cluster randomized controlled trial. International Journal of Epidemiology 40:2, 350-362
CrossRef37
Elizabeth A. Stuart, Stephen R. Cole, Catherine P. Bradshaw, Philip J. Leaf. (2011) The use of propensity scores to assess the generalizability of results from randomized trials. Journal of the Royal Statistical Society: Series A (Statistics in Society) 174:2, 369-386
CrossRef38
T. Cai, L. Tian, P. H. Wong, L. J. Wei. (2011) Analysis of randomized comparative clinical trial data for personalized treatment selections. Biostatistics 12:2, 270-282
CrossRef39
Steven A. Kaplan, Jeannette Y. Lee, Alan G. Meehan, John W. Kusek. (2011) Long-Term Treatment With Finasteride Improves Clinical Progression of Benign Prostatic Hyperplasia in Men With an Enlarged Versus a Smaller Prostate: Data From the MTOPS Trial. The Journal of Urology 185:4, 1369-1373
CrossRef40
O. Naggara, J. Raymond, F. Guilbert, D. G. Altman. (2011) The Problem of Subgroup Analyses: An Example from a Trial on Ruptured Intracranial Aneurysms. American Journal of Neuroradiology 32:4, 633-636
CrossRef41
Scot Garg, Patrick W. Serruys, Sigmund Silber, Joanna Wykrzykowska, Robert Jan van Geuns, Gert Richardt, Pawel E. Buszman, Henning Kelbæk, Adrianus Johannes van Boven, Sjoerd H. Hofma, Axel Linke, Volker Klauss, William Wijns, Carlos Macaya, Philippe Garot, Carlo DiMario, Ganesh Manoharan, Ran Kornowski, Thomas Ischinger, Antonio Bartorelli, Eric Van Remortel, Jacintha Ronden, Stephan Windecker. (2011) The Prognostic Utility of the SYNTAX Score on 1-Year Outcomes After Revascularization With Zotarolimus- and Everolimus-Eluting Stents. JACC: Cardiovascular Interventions 4:4, 432-441
CrossRef42
José Antonio Sacristán. (2011) Medicina centrada en el paciente e investigación de la efectividad comparada. Medicina Clínica 136:10, 438-440
CrossRef43
Busse, William W., Morgan, Wayne J., Gergen, Peter J., Mitchell, Herman E., Gern, James E., Liu, Andrew H., Gruchalla, Rebecca S., Kattan, Meyer, Teach, Stephen J., Pongracic, Jacqueline A., Chmiel, James F., Steinbach, Suzanne F., Calatroni, Agustin, Togias, Alkis, Thompson, Katherine M., Szefler, Stanley J., Sorkness, Christine A., . (2011) Randomized Trial of Omalizumab (Anti-IgE) for Asthma in Inner-City Children. New England Journal of Medicine 364:11, 1005-1015
Full Text44
Stacie E. Geller, Abby Koch, Beth Pellettieri, Molly Carnes. (2011) Inclusion, Analysis, and Reporting of Sex and Race/Ethnicity in Clinical Trials: Have We Made Progress?. Journal of Women's Health 20:3, 315-320
CrossRef45
Dong Hyun Sinn, Su Rin Shin, Jae Sook Kil, Jeong Kim, Geum-Youn Gwak, Moon Seok Choi, Joon Hyeok Lee, Kwang Cheol Koh, Byung Chul Yoo, Seung Woon Paik. (2011) Efficacy of peg-interferon-α-2a plus ribavirin for patients aged 60 years and older with chronic hepatitis C in Korea. Journal of Gastroenterology and Hepatology 26:3, 469-476
CrossRef46
(2011) Diets for Maintenance of Weight Loss. New England Journal of Medicine 364:8, 779-781
Full Text47
Anthony P. Delaney, Arina Dan, John McCaffrey, Simon Finfer. (2011) The role of albumin as a resuscitation fluid for patients with sepsis: A systematic review and meta-analysis*. Critical Care Medicine 39:2, 386-391
CrossRef48
Anna-Bettina Haidich, Charis Birtsou, Theodore Dardavessis, Ilias Tirodimos, Malamatenia Arvanitidou. (2011) The quality of safety reporting in trials is still suboptimal: Survey of major general medical journals. Journal of Clinical Epidemiology 64:2, 124-135
CrossRef49
Vibeke Strand, Byron Cryer, Xuemei Luo, Andrew G. Bushmakin, Joseph C. Cappelleri, Brian Cuffel, George Sands, Annlouise R. Assaf. (2011) Effect of Blood Loss on Physical Function in Arthritis Patients: A Pooled Analysis. Health Outcomes Research in Medicine 2:1, e27-e38
CrossRef50
M. Noveanu, H. Pargger, T. Breidthardt, T. Reichlin, C. Schindler, A. Heise, R. Schoenenberger, P. Manndorff, M. Siegemund, A. Mebazaa, S. Marsch, C. Mueller. (2011) Use of B-type natriuretic peptide in the management of hypoxaemic respiratory failure. European Journal of Heart Failure 13:2, 154-162
CrossRef51
Kerry Dwan, Douglas G Altman, Lynne Cresswell, Michaela Blundell, Carrol L Gamble, Paula R Williamson, Kerry Dwan. 2011. Comparison of protocols and registry entries to published reports for randomised controlled trials. .
CrossRef52
K. M. Flegal, B. I. Graubard, D. F. Williamson, R. S. Cooper. (2011) Reverse Causation and Illness-related Weight Loss in Observational Studies of Body Weight and Mortality. American Journal of Epidemiology 173:1, 1-9
CrossRef53
Sandro Barni, Roberto Labianca, Giancarlo Agnelli, Erminio Bonizzoni, Melina Verso, Mario Mandalà, Matteo Brighenti, Fausto Petrelli, Carlo Bianchini, Tania Perrone, Giampietro Gasparini. (2011) Chemotherapy-associated thromboembolic risk in cancer outpatients and effect of nadroparin thromboprophylaxis: results of a retrospective analysis of the PROTECHT study. Journal of Translational Medicine 9:1, 179
CrossRef54
José A Sacristán. (2011) Exploratory trials, confirmatory observations: A new reasoning model in the era of patient-centered medicine. BMC Medical Research Methodology 11:1, 57
CrossRef55
Karim F Hirji, Zulfiqarali G Premji. (2011) Pre-referral rectal artesunate in severe malaria: flawed trial. Trials 12:1, 188
CrossRef56
The EINSTEIN Investigators. (2010) Oral Rivaroxaban for Symptomatic Venous Thromboembolism. New England Journal of Medicine 363:26, 2499-2510
Full Text57
Bradley S Quon, J. Mark FitzGerald, Catherine Lemière, Neal Shahidi, Francine M Ducharme, Francine M Ducharme. 2010. Increased versus stable doses of inhaled corticosteroids for exacerbations of chronic asthma in adults and children. .
CrossRef58
M. J. Bolland, A. Grey, G. D. Gamble, I. R. Reid. (2010) Investigating harms in clinical trials - no easy task. International Journal of Clinical Practice 64:13, 1719-1722
CrossRef59
H. J. Lambers Heerspink, T. Ninomiya, V. Perkovic, M. Woodward, S. Zoungas, A. Cass, M. Cooper, D. E. Grobbee, G. Mancia, C. E. Mogensen, B. Neal, J. Chalmers, . (2010) Effects of a fixed combination of perindopril and indapamide in patients with type 2 diabetes and chronic kidney disease. European Heart Journal 31:23, 2888-2896
CrossRef60
Roy M. John. (2010) Prerenal failure and response to cardiac resynchronization therapy: Making a case for the sicker patients deriving greater benefit?. Heart Rhythm 7:12, 1783-1784
CrossRef61
Thilinie Rajapakse, Tamara Pringsheim. (2010) Pharmacotherapeutics of Tourette Syndrome and Stereotypies in Autism. Seminars in Pediatric Neurology 17:4, 254-260
CrossRef62
Esther S.T.F. Smeulders, Jolanda C.M. van Haastregt, Ton Ambergen, Henri E.J.H. Stoffers, Josiane J.J. Janssen-Boyne, Nicole H.K.M. Uszko-Lencer, Anton P.M. Gorgels, Cara L.B. Lodewijks-van der Bolt, Jacques Th.M. van Eijk, Gertrudis I.J.M. Kempen. (2010) Heart failure patients with a lower educational level and better cognitive status benefit most from a self-management group programme. Patient Education and Counseling 81:2, 214-221
CrossRef63
Charles J. Holahan, Kathleen K. Schutte, Penny L. Brennan, Carole K. Holahan, Bernice S. Moos, Rudolf H. Moos. (2010) Late-Life Alcohol Consumption and 20-Year Mortality. Alcoholism: Clinical and Experimental Research 34:11, 1961-1971
CrossRef64
Kenji Kawakami, Yasushi Ohkusa, Reiki Kuroki, Takeshi Tanaka, Kazuhiko Koyama, Yoshitaka Harada, Kouichi Iwanaga, Takeshi Yamaryo, Kazunori Oishi. (2010) Effectiveness of pneumococcal polysaccharide vaccine against pneumonia and cost analysis for the elderly who receive seasonal influenza vaccine in Japan. Vaccine 28:43, 7063-7069
CrossRef65
Scott R. Serels, Marc R. Toglia, Sergio Forero-Schwanhaeuser, Weizhong He. (2010) Impact of solifenacin on diary-recorded and patient-reported urgency in patients with severe overactive bladder (OAB) symptoms. Current Medical Research and Opinion 26:10, 2277-2285
CrossRef66
H. Zhang, R. S. Legro, J. Zhang, L. Zhang, X. Chen, H. Huang, P. R. Casson, W. D. Schlaff, M. P. Diamond, S. A. Krawetz, C. Coutifaris, R. G. Brzyski, G. M. Christman, N. Santoro, E. Eisenberg, . (2010) Decision trees for identifying predictors of treatment effectiveness in clinical trials and its application to ovulation in a study of women with polycystic ovary syndrome. Human Reproduction 25:10, 2612-2621
CrossRef67
Sciurba, Frank C., Ernst, Armin, Herth, Felix J.F., Strange, Charlie, Criner, Gerard J., Marquette, Charles H., Kovitz, Kevin L., Chiacchierini, Richard P., Goldin, Jonathan, McLennan, Geoffrey, . (2010) A Randomized Study of Endobronchial Valves for Advanced Emphysema. New England Journal of Medicine 363:13, 1233-1244
Full Text68
Decousus, Hervé, Prandoni, Paolo, Mismetti, Patrick, Bauersachs, Rupert M., Boda, Zoltán, Brenner, Benjamin, Laporte, Silvy, Matyas, Lajos, Middeldorp, Saskia, Sokurenko, German, Leizorovicz, Alain, . (2010) Fondaparinux for the Treatment of Superficial-Vein Thrombosis in the Legs. New England Journal of Medicine 363:13, 1222-1232
Full Text69
C. Warren Olanow, Karl Kieburtz. (2010) Defining disease-modifying therapies for PD-A road map for moving forward. Movement Disorders 25:12, 1774-1779
CrossRef70
Appel, Lawrence J., Wright, Jackson T. Jr., Greene, Tom, Agodoa, Lawrence Y., Astor, Brad C., Bakris, George L., Cleveland, William H., Charleston, Jeanne, Contreras, Gabriel, Faulkner, Marquetta L., Gabbai, Francis B., Gassman, Jennifer J., Hebert, Lee A., Jamerson, Kenneth A., Kopple, Joel D., Kusek, John W., Lash, James P., Lea, Janice P., Lewis, Julia B., Lipkowitz, Michael S., Massry, Shaul G., Miller, Edgar R., Norris, Keith, Phillips, Robert A., Pogue, Velvie A., Randall, Otelio S., Rostand, Stephen G., Smogorzewski, Miroslaw J., Toto, Robert D., Wang, Xuelei, . (2010) Intensive Blood-Pressure Control in Hypertensive Chronic Kidney Disease. New England Journal of Medicine 363:10, 918-929
Full Text71
Gerald Liew, Ronald Klein, Tien Y. Wong. (2010) The Role of Genetics in Susceptibility to Diabetic Retinopathy. International Ophthalmology Clinics 49:2, 35-52
CrossRef72
Faramarz Ismail-Beigi, Timothy Craven, Mary Ann Banerji, Jan Basile, Jorge Calles, Robert M Cohen, Robert Cuddihy, William C Cushman, Saul Genuth, Richard H Grimm, Bruce P Hamilton, Byron Hoogwerf, Diane Karl, Lois Katz, Armand Krikorian, Patrick O'Connor, Rodica Pop-Busui, Ulrich Schubart, Debra Simmons, Harris Taylor, Abraham Thomas, Daniel Weiss, Irene Hramiak. (2010) Effect of intensive treatment of hyperglycaemia on microvascular outcomes in type 2 diabetes: an analysis of the ACCORD randomised trial. The Lancet 376:9739, 419-430
CrossRef73
The HEALTHY Study Group. (2010) A School-Based Intervention for Diabetes Risk Reduction. New England Journal of Medicine 363:5, 443-453
Full Text74
Rea, Thomas D., Fahrenbruch, Carol, Culley, Linda, Donohoe, Rachael T., Hambly, Cindy, Innes, Jennifer, Bloomingdale, Megan, Subido, CleoRomines, Steven, Eisenberg, Mickey S., . (2010) CPR with Chest Compression Alone or with Rescue Breathing. New England Journal of Medicine 363:5, 423-433
Full Text75
Stone, John H., Merkel, Peter A., Spiera, Robert, Seo, Philip, Langford, Carol A., Hoffman, Gary S., Kallenberg, Cees G.M., St. Clair, E. William, Turkiewicz, Anthony, Tchao, Nadia K., Webber, Lisa, Ding, Linna, Sejismundo, Lourdes P., Mieras, Kathleen, Weitzenkamp, David, Ikle, David, Seyfert-Margolis, Vicki, Mueller, Mark, Brunetta, Paul, Allen, Nancy B., Fervenza, Fernando C., Geetha, Duvuru, Keogh, Karina A., Kissin, Eugene Y., Monach, Paul A., Peikert, Tobias, Stegeman, Coen, Ytterberg, Steven R., Specks, Ulrich, . (2010) Rituximab versus Cyclophosphamide for ANCA-Associated Vasculitis. New England Journal of Medicine 363:3, 221-232
Full Text76
Joanna J. Wykrzykowska, Scot Garg, Chrysafios Girasis, Ton de Vries, Marie-Angele Morel, Gerrit-Anne van Es, Pawel Buszman, Axel Linke, Thomas Ischinger, Volker Klauss, Roberto Corti, Franz Eberli, William Wijns, Marie-Claude Morice, Carlo di Mario, Robert Jan van Geuns, Peter Juni, Stephan Windecker, Patrick W. Serruys. (2010) Value of the SYNTAX Score for Risk Assessment in the All-Comers Population of the Randomized Multicenter LEADERS (Limus Eluted from A Durable versus ERodable Stent coating) Trial. Journal of the American College of Cardiology 56:4, 272-277
CrossRef77
Matthew R Sydes, Ruth E Langley. (2010) Potential pitfalls in the design and reporting of clinical trials. The Lancet Oncology 11:7, 694-700
CrossRef78
Young-Hak Kim, Duk-Woo Park, Won-Jang Kim, Jong-Young Lee, Sung-Cheol Yun, Soo-Jin Kang, Seung-Whan Lee, Cheol Whan Lee, Myeong-Ki Hong, Seong-Wook Park, Seung-Jung Park. (2010) Impact of the Extent of Coronary Artery Disease on Outcomes After Revascularization for Unprotected Left Main Coronary Artery Stenosis. Journal of the American College of Cardiology 55:23, 2544-2552
CrossRef79
Todd M. Manini, Anne B. Newman, Roger Fielding, Steven N. Blair, Michael G. Perri, Stephen D. Anton, Bret C. Goodpaster, Jeff A. Katula, Walter J. Rejeski, Stephen B. Kritchevsky, Fang-Chi Hsu, Marco Pahor. (2010) Effects of Exercise on Mobility in Obese and Nonobese Older Adults. Obesity 18:6, 1168-1175
CrossRef80
Mohammad F. Huque, Mohamed Alosh, Satya D. Dubey, Rafia Bhore. 2010. P -Values, Evidence, and Multiplicity Considerations for Controlled Clinical Trials. , 949-961.
CrossRef81
Marion Doull, Vivien E. Runnels, Sari Tudiver, Madeline Boscoe. (2010) Appraising the Evidence: Applying Sex- and Gender-Based Analysis (SGBA) to Cochrane Systematic Reviews on Cardiovascular Diseases. Journal of Women's Health 19:5, 997-1003
CrossRef82
Jaykaran ., P. Yadav, N. Chavda, N.D. Kantharia. (2010) Some Issues Related to the Reporting of Statistics in Clinical Trials Published in Indian Medical Journals: A Survey. International Journal of Pharmacology 6:4, 354-359
CrossRef83
Peter G. Davis, Barbara Schmidt, Robin S. Roberts, Lex W. Doyle, Elizabeth Asztalos, Ross Haslam, Sunil Sinha, Win Tin. (2010) Caffeine for Apnea of Prematurity Trial: Benefits May Vary in Subgroups. The Journal of Pediatrics 156:3, 382-387.e3
CrossRef84
J. M. Sargeant, A. M. O’Connor, I. A. Gardner, J. S. Dickson, M. E. Torrence, , I. R. Dohoo, S. L. Lefebvre, P. S. Morley, A. Ramirez, K. Snedeker. (2010) The REFLECT Statement: Reporting Guidelines for Randomized Controlled Trials in Livestock and Food Safety: Explanation and Elaboration. Zoonoses and Public Health 57:2, 105-136
CrossRef85
Justine Rouette, Helen Trottier, Thierry Ducruet, Mona Beaunoyer, Jacques Lacroix, Marisa Tucci. (2010) Red Blood Cell Transfusion Threshold in Postsurgical Pediatric Intensive Care Patients. Annals of Surgery 251:3, 421-427
CrossRef86
Sanjay Kaul, George A. Diamond. (2010) Trial and Error. Journal of the American College of Cardiology 55:5, 415-427
CrossRef87
Stefanos Bonovas, Georgios Nikolopoulos, Nikolaos M. Sitaras. (2010) Commentary on pravastatin and cancer: need for individual patient data meta-analyses. Pharmacoepidemiology and Drug Safety 19:2, 203-204
CrossRef88
Ariane Willems, Karen Harrington, Jacques Lacroix, Dominique Biarent, Ari R. Joffe, David Wensley, Thierry Ducruet, Paul C. Hébert, Marisa Tucci. (2010) Comparison of two red-cell transfusion strategies after pediatric cardiac surgery: A subgroup analysis. Critical Care Medicine 38:2, 649-656
CrossRef89
Erik Fernandez y Garcia, Hien Nguyen, Naihua Duan, Nicole B. Gabler, Richard L. Kravitz. (2010) Assessing Heterogeneity of Treatment Effects: Are Authors Misinterpreting Their Results?. Health Services Research 45:1, 283-301
CrossRef90
Archana B. Patel, Michael J. Dibley, Manju Mamtani, Neetu Badhoniya, Hemant Kulkarni. (2010) Influence of Zinc Supplementation in Acute Diarrhea Differs by the Isolated Organism. International Journal of Pediatrics 2010, 1-9
CrossRef91
Michael C. Reade, Anthony Delaney, Michael J. Bailey, David A. Harrison, Donald M. Yealy, Peter G. Jones, Kathryn M. Rowan, Rinaldo Bellomo, Derek C. Angus. (2010) Prospective meta-analysis using individual patient data in intensive care medicine. Intensive Care Medicine 36:1, 11-21
CrossRef92
Shian-Shiang Wang, Yen-Chuan Ou, Chen-Li Cheng, Philipp Dahm, . (2010) Evidence-based urology in practice: when to believe a subgroup analysis?. BJU International 105:2, 162-164
CrossRef93
Marco Bonetti, Chiara Gigliarano, Pietro Muliere. (2009) The Gini concentration test for survival data. Lifetime Data Analysis 15:4, 493-518
CrossRef94
The RENAL Replacement Therapy Study Investigators. (2009) Intensity of Continuous Renal-Replacement Therapy in Critically Ill Patients. New England Journal of Medicine 361:17, 1627-1638
Full Text95
W. L. Baker, C. Michael White, J. C. Cappelleri, J. Kluger, C. I. Coleman, . (2009) Understanding heterogeneity in meta-analysis: the role of meta-regression. International Journal of Clinical Practice 63:10, 1426-1434
CrossRef96
Chris P. Miller, Kimberly A. Lowe, Karine Valliant-Saunders, Joringel F. Kaiser, Dominik Mattern, Nicole Urban, Michael Henke, C. Anthony Blau. (2009) Evaluating Erythropoietin-Associated Tumor Progression Using Archival Tissues from a Phase III Clinical Trial. Stem Cells 27:9, 2353-2361
CrossRef97
Ratna Sircar, Ashim K. Basak, Debashish Sircar. (2009) Repeated ethanol exposure affects the acquisition of spatial memory in adolescent female rats. Behavioural Brain Research 202:2, 225-231
CrossRef98
J H Powers, T R Fleming. (2009) Design, Conduct, and Analysis of Clinical Trials in Disease due to Methicillin-Resistant Staphylococcus aureus. Clinical Pharmacology & Therapeutics 86:3, 244-247
CrossRef99
The BIG 1-98 Collaborative Group. (2009) Letrozole Therapy Alone or in Sequence with Tamoxifen in Women with Breast Cancer. New England Journal of Medicine 361:8, 766-776
Full Text100
Christopher G Wood, Peter Mulders. (2009) Vitespen: a preclinical and clinical review. Future Oncology 5:6, 763-774
CrossRef101
J. M. Friedman. (2009) Big risks in small groups: The difference between epidemiology and counselling. Birth Defects Research Part A: Clinical and Molecular Teratology 85:8, 720-724
CrossRef102
Suhayl Tafazal, Leslie Ng, Neeraj Chaudhary, Philip Sell. (2009) Corticosteroids in peri-radicular infiltration for radicular pain: a randomised double blind controlled trial. One year results and subgroup analysis. European Spine Journal 18:8, 1220-1225
CrossRef103
Rob S.B. Beanlands, Maria Cecilia Ziadi, Kathryn Williams. (2009) Quantification of Myocardial Flow Reserve Using Positron Emission Imaging. Journal of the American College of Cardiology 54:2, 157-159
CrossRef104
Jonas Z Hines, Peter Lurie, Sidney M Wolfe. (2009) Post Hoc Analysis Does Not Establish Effectiveness of rTMS for Depression. Neuropsychopharmacology 34:8, 2053-2054
CrossRef105
Jean-Christian Borel, Samuel Verges, Jean-Louis Pepin, Isabelle Vivodtzev, Patrick Levy, Bernard Wuyam. (2009) Home exercise training with non-invasive ventilation in thoracic restrictive respiratory disorders: A randomised study. Respiratory Physiology & Neurobiology 167:2, 168-173
CrossRef106
Peter M. Fayers, Madeleine T. King. (2009) How to guarantee finding a statistically significant difference: the use and abuse of subgroup analyses. Quality of Life Research 18:5, 527-530
CrossRef107
Stuart J Pocock, James H Ware. (2009) Translating statistical findings into plain English. The Lancet 373:9679, 1926-1928
CrossRef108
Theodoros I. Kassimatis, Panagiotis A. Konstantinopoulos. (2009) The role of statins in chronic kidney disease (CKD): Friend or foe?. Pharmacology & Therapeutics 122:3, 312-323
CrossRef109
K. Z. Vardakas, D. K. Matthaiou, M. E. Falagas. (2009) Adjunctive dexamethasone therapy for bacterial meningitis in adults: a meta-analysis of randomized controlled trials. European Journal of Neurology 16:6, 662-673
CrossRef110
Mario Cottone, Filippo Mocciaro, Ambrogio Orlando. (2009) Infliximab prevents Crohn’s disease recurrence after ileal resection. Expert Review of Gastroenterology & Hepatology 3:3, 231-234
CrossRef111
(2009) Oral Corticosteroids in Children with Wheezing. New England Journal of Medicine 360:16, 1673-1676
Full Text112
Marco Bonetti, David Zahrieh, Bernard F. Cole, Richard D. Gelber. (2009) A small sample study of the STEPP approach to assessing treatment-covariate interactions in survival data. Statistics in Medicine 28:8, 1255-1268
CrossRef113
Christophe Dupont, Jimmy Lee Kok Foo, Philippe Garnier, Nicholas Moore, Hèlène Mathiex–Fortunet, Eduardo Salazar–Lindo. (2009) Oral Diosmectite Reduces Stool Output and Diarrhea Duration in Children With Acute Watery Diarrhea. Clinical Gastroenterology and Hepatology 7:4, 456-462
CrossRef114
T Sawada, T Takahashi, H Yamada, B Dahlöf, H Matsubara. (2009) Rationale and design of the KYOTO HEART study: effects of valsartan on morbidity and mortality in uncontrolled hypertensive patients with high risk of cardiovascular events. Journal of Human Hypertension 23:3, 188-195
CrossRef115
, M. Hutchinson, L. Kappos, P. A. Calabresi, C. Confavreux, G. Giovannoni, S. L. Galetta, E. Havrdova, F. D. Lublin, D. H. Miller, P. W. O’Connor, J. T. Phillips, C. H. Polman, E.-W. Radue, R. A. Rudick, W. H. Stuart, A. Wajgt, B. Weinstock-Guttman, D. R. Wynn, F. Lynn, M. A. Panzara. (2009) The efficacy of natalizumab in patients with relapsing multiple sclerosis: subgroup analyses of AFFIRM and SENTINEL. Journal of Neurology 256:3, 405-415
CrossRef116
Peter Herbison. (2009) Predicting who will benefit from treatment. Neurourology and Urodynamics 28:3, 168-169
CrossRef117
Djillali Annane. (2009) Vasopressin plus corticosteroids: The shock duo!*. Critical Care Medicine 37:3, 1126-1127
CrossRef118
Ajith P. Nair, Bruce Darrow. (2009) Lipid Management in the Geriatric Patient. Endocrinology & Metabolism Clinics of North America 38:1, 185-206
CrossRef119
Claus G. Roehrborn, Paul Siami, Jack Barkin, Ronaldo Damião, Edgardo Becher, Bernardino Miñana, Vicenzo Mirone, Ramiro Castro, Timothy Wilson, Francesco Montorsi. (2009) The Influence of Baseline Parameters on Changes in International Prostate Symptom Score with Dutasteride, Tamsulosin, and Combination Therapy among Men with Symptomatic Benign Prostatic Hyperplasia and an Enlarged Prostate: 2-Year Data from the CombAT Study. European Urology 55:2, 461-471
CrossRef120
B. D. Lawenda, J. B. Blumberg. (2009) Response: Re: Should Supplemental Antioxidant Administration Be Avoided During Chemotherapy and Radiation Therapy?. JNCI Journal of the National Cancer Institute 101:2, 125-126
CrossRef121
Moers, Cyril, Smits, Jacqueline M., Maathuis, Mark-Hugo J., Treckmann, Jürgen, van Gelder, FrankNapieralski, Bogdan P.van Kasterop-Kutz, Margittavan der Heide, Jaap J. Homan, Squifflet, Jean-Paul, van Heurn, Ernest, Kirste, Günter R., Rahmel, Axel, Leuvenink, Henri G.D., Paul, Andreas, Pirenne, Jacques, Ploeg, Rutger J., . (2009) Machine Perfusion or Cold Storage in Deceased-Donor Kidney Transplantation. New England Journal of Medicine 360:1, 7-19
Full Text122
Emilio Bria, Richard J. Gralla, Harry Raftopoulos, Federica Cuppone, Michele Milella, Isabella Sperduti, Paolo Carlini, Edmondo Terzoli, Francesco Cognetti, Diana Giannarelli. (2009) Magnitude of benefit of adjuvant chemotherapy for non-small cell lung cancer: Meta-analysis of randomized clinical trials. Lung Cancer 63:1, 50-57
CrossRef123
Ellen W. Seely, Steven Grinspoon. 2009. Patient-Oriented ResearchClinical Pathophysiology and Clinical Therapeutics. , 3-12.
CrossRef124
W. F. Anderson, P. S. Rosenberg, I. Menashe, A. Mitani, R. M. Pfeiffer. (2008) Age-Related Crossover in Breast Cancer Incidence Rates Between Black and White Ethnic Groups. JNCI Journal of the National Cancer Institute 100:24, 1804-1814
CrossRef125
Di Bisceglie, Adrian M., Shiffman, Mitchell L., Everson, Gregory T., Lindsay, Karen L., Everhart, James E., Wright, Elizabeth C., Lee, William M., Lok, Anna S., Bonkovsky, Herbert L., Morgan, Timothy R., Ghany, Marc G., Morishima, Chihiro, Snow, Kristin K., Dienstag, Jules L., . (2008) Prolonged Therapy of Advanced Chronic Hepatitis C with Low-Dose Peginterferon. New England Journal of Medicine 359:23, 2429-2441
Full Text126
Fred R. Hirsch, Anna Spreafico, Silvia Novello, Mary Dugan Wood, Lorinda Simms, Mauro Papotti. (2008) The Prognostic and Predictive Role of Histology in Advanced Non-small Cell Lung Cancer. Journal of Thoracic Oncology 3:12, 1468-1481
CrossRef127
Michael Rawlins. (2008) De testimonio: on the evidence for decisions about the use of therapeutic interventions. The Lancet 372:9656, 2152-2161
CrossRef128
Caitlin Ravichandran, Garrett M. Fitzmaurice. (2008) A tale of two nutritionists (or the importance of analysis plans). Nutrition 24:11-12, 1227-1228
CrossRef129
Morris, Brenda H., Oh, William, Tyson, Jon E., Stevenson, David K., Phelps, Dale L., O'Shea, T. Michael, McDavid, Georgia E., Perritt, Rebecca L., Van Meurs, Krisa P., Vohr, Betty R., Grisby, Cathy, Yao, Qing, Pedroza, Claudia, Das, Abhik, Poole, W. Kenneth, Carlo, Waldemar A., Duara, Shahnaz, Laptook, Abbot R., Salhab, Walid A., Shankaran, Seetha, Poindexter, Brenda B., Fanaroff, Avroy A., Walsh, Michele C., Rasmussen, Maynard R., Stoll, Barbara J., Cotten, C. Michael, Donovan, Edward F., Ehrenkranz, Richard A., Guillet, Ronnie, Higgins, Rosemary D., . (2008) Aggressive vs. Conservative Phototherapy for Infants with Extremely Low Birth Weight. New England Journal of Medicine 359:18, 1885-1896
Full Text130
Bochud, Pierre-Yves, Chien, Jason W., Marr, Kieren A., Leisenring, Wendy M., Upton, Arlo, Janer, Marta, Rodrigues, Stephanie D.Li, SarahHansen, John A., Zhao, Lue Ping, Aderem, Alan, Boeckh, Michael, . (2008) Toll-like Receptor 4 Polymorphisms and Aspergillosis in Stem-Cell Transplantation. New England Journal of Medicine 359:17, 1766-1777
Full Text131
(2008) Age-Related Macular Degeneration. New England Journal of Medicine 359:16, 1735-1736
Full Text132
Fätkenheuer, Gerd, Nelson, Mark, Lazzarin, Adriano, Konourina, Irina, Hoepelman, Andy I.M., Lampiris, Harry, Hirschel, Bernard, Tebas, Pablo, Raffi, François, Trottier, Benoit, Bellos, Nicholaos, Saag, Michael, Cooper, David A., Westby, Mike, Tawadrous, Margaret, Sullivan, John F., Ridgway, Caroline, Dunne, Michael W., Felstead, Steve, Mayer, Howard, van der Ryst, Elna, . (2008) Subgroup Analyses of Maraviroc in Previously Treated R5 HIV-1 Infection. New England Journal of Medicine 359:14, 1442-1455
Full Text133
John P. A. Ioannidis. (2008) Interpretation of tests of heterogeneity and bias in meta-analysis. Journal of Evaluation in Clinical Practice 14:5, 951-957
CrossRef134
Vermorken, Jan B., Mesia, Ricard, Rivera, Fernando, Remenar, Eva, Kawecki, Andrzej, Rottey, Sylvie, Erfan, Jozsef, Zabolotnyy, Dmytro, Kienzer, Heinz-Roland, Cupissol, Didier, Peyrade, Frederic, Benasso, Marco, Vynnychenko, Ihor, De Raucourt, Dominique, Bokemeyer, Carsten, Schueler, Armin, Amellal, Nadia, Hitt, Ricardo, . (2008) Platinum-Based Chemotherapy plus Cetuximab in Head and Neck Cancer. New England Journal of Medicine 359:11, 1116-1127
Full Text135
Kathleen Uhl, Sherry Marts. (2008) Assessing sex differences: methodological considerations. Expert Review of Clinical Pharmacology 1:5, 585-587
CrossRef136
Emanuel Sporn, J. Wade Davis, Klaus Thaler, Brent W. Miedema. (2008) Sentinel node mapping during laparoscopic distal gastrectomy for gastric cancer. Surgical Endoscopy 22:9, 2097-2097
CrossRef137
Brian M. Ilfeld, Scott T. Ball, Peter F. Gearen, Linda T. Le, Edward R. Mariano, Krista Vandenborne, Pamela W. Duncan, Daniel I. Sessler, F Kayser Enneking, Jonathan J. Shuster, Douglas W. Theriaque, R Scott Meyer. (2008) Ambulatory Continuous Posterior Lumbar Plexus Nerve Blocks after Hip Arthroplasty. Anesthesiology 109:3, 491-501
CrossRef138
Stanley J Szefler, Herman Mitchell, Christine A Sorkness, Peter J Gergen, George T O'Connor, Wayne J Morgan, Meyer Kattan, Jacqueline A Pongracic, Stephen J Teach, Gordon R Bloomberg, Peyton A Eggleston, Rebecca S Gruchalla, Carolyn M Kercsmar, Andrew H Liu, Jeremy J Wildfire, Matthew D Curry, William W Busse. (2008) Management of asthma based on exhaled nitric oxide in addition to guideline-based treatment for inner-city adolescents and young adults: a randomised controlled trial. The Lancet 372:9643, 1065-1072
CrossRef139
J. D. Schold, B. Kaplan. (2008) Design and Analysis of Clinical Trials in Transplantation: Principles and Pitfalls. American Journal of Transplantation 8:9, 1779-1785
CrossRef140
Kastrati, Adnan, Neumann, Franz-Josef, Mehilli, Julinda, Byrne, Robert A., Iijima, Raisuke, Büttner, Heinz Joachim, Khattab, Ahmed A., Schulz, Stefanie, Blankenship, James C., Pache, Jürgen, Minners, Jan, Seyfarth, Melchior, Graf, Isolde, Skelding, Kimberly A., Dirschinger, Josef, Richardt, Gert, Berger, Peter B., Schömig, Albert, . (2008) Bivalirudin versus Unfractionated Heparin during Percutaneous Coronary Intervention. New England Journal of Medicine 359:7, 688-696
Full Text141
Cooper, David A., Steigbigel, Roy T., Gatell, Jose M., Rockstroh, Jurgen K., Katlama, Christine, Yeni, Patrick, Lazzarin, Adriano, Clotet, Bonaventura, Kumar, Princy N., Eron, Joseph E., Schechter, Mauro, Markowitz, Martin, Loutfy, Mona R., Lennox, Jeffrey L., Zhao, Jing, Chen, Joshua, Ryan, Desmond M., Rhodes, Rand R., Killar, John A., Gilde, Lucinda R., Strohmaier, Kim M., Meibohm, Anne R., Miller, Michael D., Hazuda, Daria J., Nessly, Michael L., DiNubile, Mark J., Isaacs, Robin D., Teppler, Hedy, Nguyen, Bach-Yen, . (2008) Subgroup and Resistance Analyses of Raltegravir for Resistant HIV-1 Infection. New England Journal of Medicine 359:4, 355-365
Full Text142
Gueugniaud, Pierre-Yves, David, Jean-Stéphane, Chanzy, Eric, Hubert, Hervé, Dubien, Pierre-Yves, Mauriaucourt, Patrick, Bragança, Coralie, Billères, Xavier, Clotteau-Lambert, Marie-Paule, Fuster, Patrick, Thiercelin, Didier, Debaty, Guillaume, Ricard-Hibon, Agnès, Roux, Patrick, Espesson, Catherine, Querellou, Emgan, Ducros, Laurent, Ecollan, Patrick, Halbout, Laurent, Savary, Dominique, Guillaumée, Frédéric, Maupoint, Régine, Capelle, Philippe, Bracq, Cécile, Dreyfus, Philippe, Nouguier, Philippe, Gache, Antoine, Meurisse, Claude, Boulanger, Bertrand, Lae, Claude, Metzger, Jacques, Raphael, Valérie, Beruben, Arielle, Wenzel, Volker, Guinhouya, Comlavi, Vilhelm, Christian, Marret, Emmanuel, . (2008) Vasopressin and Epinephrine vs. Epinephrine Alone in Cardiopulmonary Resuscitation. New England Journal of Medicine 359:1, 21-30
Full Text143
Tetsuji Fujita. (2008) Influence of Preoperative Inflammation on Outcomes of Colorectal Cancer Surgery. Annals of Surgery 247:6, 1084-1085
CrossRef144
Abby C. King, David F. Ahn, Audie A. Atienza, Helena C. Kraemer. (2008) Exploring Refinements in Targeted Behavioral Medicine Intervention to Advance Public Health. Annals of Behavioral Medicine 35:3, 251-260
CrossRef145
(2008) More on Subgroup Analyses in Clinical Trials. New England Journal of Medicine 358:19, 2076-2077
Full Text146
Penelope M. A. Brasher, Rollin F. Brant. (2008) Problems of multiplicity. Canadian Journal of Anesthesia/Journal canadien d'anesthésie 55:5, 259-264
CrossRef147
John H. Powers. (2008) Editorial Commentary: Reassessing the Design, Conduct, and Analysis of Clinical Trials of Therapy for Community‐Acquired Pneumonia. Clinical Infectious Diseases 46:8, 1152-1156
CrossRef148
(2008) Subgroup Analyses in Clinical Trials. New England Journal of Medicine 358:11, 1199-1200
Full Text149
Ari R. Joffe, Jonathan P. Duff. (2008) Commentary on ‘Human recombinant activated protein C for severe sepsis’. Evidence-Based Child Health: A Cochrane Review Journal 3:1, 141-143
CrossRef150
Gerrit Hennecke, Clemens R Scherzer. (2008) RNA biomarkers of Parkinson’s disease: developing tools for novel therapies. Biomarkers in Medicine 2:1, 41-53
CrossRef151
Stephen J W Evans. (2008) Stratification for Spontaneous Report Databases. Drug Safety 31:11, 1049-1052
CrossRef152
Heleen Riper, Jeannet Kramer, Max Keuken, Filip Smit, Gerard Schippers, Pim Cuijpers. (2008) Predicting Successful Treatment Outcome of Web-Based Self-help for Problem Drinkers: Secondary Analysis From a Randomized Controlled Trial. Journal of Medical Internet Research 10:4, e46
CrossRef
- Letters
