Join the 200th Anniversary Celebration

Special Article

Relationship between Number of Medical Conditions and Quality of Care

Takahiro Higashi, M.D., Ph.D., Neil S. Wenger, M.D., M.P.H., John L. Adams, Ph.D., Constance Fung, M.D., M.S.H.S., Martin Roland, D.M., Elizabeth A. McGlynn, Ph.D., David Reeves, Ph.D., Steven M. Asch, M.D., M.P.H., Eve A. Kerr, M.D., M.P.H., and Paul G. Shekelle, M.D., Ph.D.

N Engl J Med 2007; 356:2496-2504June 14, 2007

Abstract

Background

There is emerging concern that the methods used to measure the quality of care unfairly penalize providers caring for patients with multiple chronic conditions. We therefore sought to study the relationship between the quality of care and the number of medical conditions a patient has.

Methods

We assessed measurements of the quality of medical care received in three cohorts of community-dwelling adult patients in the Community Quality Index study, the Assessing Care of Vulnerable Elders study, and the Veterans Health Administration project (7680 patients in total). We analyzed the relationship between the quality of care that patients received, defined as the percentage of quality indicators satisfied among those for which patients were eligible, and the number of chronic medical conditions each patient had. We further explored the roles of characteristics of patients, use of health care (number of office visits and hospitalizations), and care provided by specialists as explanations for the observed relationship.

Results

The quality of care increased as the number of medical conditions increased. Each additional condition was associated with an increase in the quality score of 2.2% (95% confidence interval [CI], 1.7 to 2.7) in the Community Quality Index cohort, of 1.7% (95% CI, 1.1 to 2.4) in the Assessing Care of Vulnerable Elders cohort, and of 1.7% (95% CI, 0.7 to 2.8) in the Veterans Health Administration cohort. The relationship between the quality of care and the number of conditions was little affected by adjustment for the difficulty of delivering the care recommended in a quality indicator and for the fact that, because of multiple conditions requiring the same care, a patient could be eligible to receive the same care process more than once. Adjustment for characteristics of patients, use of health care, and care provided by specialists diminished the relationship, but it remained positive.

Conclusions

The quality of care, measured according to whether patients were offered recommended services, increases as a patient's number of chronic conditions increases.

Media in This Article

Figure 1Relationship between Number of Chronic Conditions and Quality of Health Care in Each of the Three Cohorts.
Figure 2Effect of Adjustment for Measurement Artifacts on the Relationship between Number of Chronic Conditions and Quality Score.
Article

Evidence-based quality indicators, developed by a wide array of groups,1-4 are increasingly being used to evaluate providers5,6 and to promote both transparency of care and competition based on quality.7,8 In pay-for-performance programs, reimbursement is linked to performance measured with the use of such quality metrics.9-11

Quality indicators are typically developed for patients with one condition. Yet many patients have multiple conditions of varying severity. Sixty-five percent of Medicare beneficiaries have more than one condition, and almost 32% have four or more.11,12 Furthermore, physicians and systems provide care for patients with conditions that vary in complexity.

As interest in public reporting and pay-for-performance programs grows, many worry that providers who treat patients with more complex conditions will be unfairly penalized, with unintended consequences.13-15 Some prevailing concerns are that existing sets of performance measures do not adequately account for the number and severity of conditions16,17 or for the presence of specific conditions, such as major depression, that may affect the care of other conditions.18,19 Concerns about physicians having insufficient time to address the many needs of patients with multiple coexisting conditions have been bolstered by the results of simulation studies that show the mismatch between the time available to perform the vast number of recommended care processes and the time and personnel resources available to a typical primary care provider.20,21 Additional concerns are that the treatment of vulnerable subgroups such as homeless patients or patients with uncommon conditions, whose clinical needs and priorities may not be adequately represented in sets of performance measurements,22,23 will suffer if pay-for-performance programs create incentives that are misaligned with the needs of patients with complex conditions.

However, there is little empirical information about the influence of the number of chronic conditions on the quality of care. We therefore evaluated the variation in quality of care as the number of chronic conditions increases. We used clinically detailed data sets from three separate studies of various populations that measured disease-specific and aggregate quality of care for more than 7500 patients, 956 of whom had three or more chronic conditions.

Methods

Patient Populations

We analyzed data for patients in the Community Quality Index (CQI) study,4 the Assessing Care of Vulnerable Elders (ACOVE) study,24,25 and the Veterans Health Administration (VHA) quality-of-care project.26 A total of 6712 adults living in 12 metropolitan areas across the United States were enrolled in the CQI study between October 1998 and August 2000. They were asked to complete a telephone interview regarding their health care experiences in the 2 years before the interview and to provide written informed consent to obtain copies of their medical records from all providers. All patients provided such consent.

ACOVE recruited 372 vulnerable older patients, defined as community-dwelling persons aged 65 years or older who were at increased risk for death or functional decline, through two large managed-care organizations. Randomly selected patients were contacted by telephone between October 1999 and January 2000, and those who were determined to be at increased risk according to the Vulnerable Elders Survey–13 scale were included in that study.27 All patients provided written informed consent.

The VHA project involved 596 male veterans, aged 35 years or older, who were receiving care at 26 clinical sites in 12 systems of two Veterans Integrated Service Networks. These veterans received care from a participating VHA facility at least once in each of the 2 years between October 1997 and September 1999. The institutional review boards of the VHA waived the requirement for written informed consent.

The study protocols of the three projects were approved by the RAND institutional review board. The VHA project was approved by the institutional review boards of individual VHA facilities.

Measurement of the Quality of Care

In all three projects, the quality of care was measured with the use of quality indicators related to care processes.4,24,26 Each quality indicator specified which patients were eligible and which care processes the eligible patients should receive. These quality indicators were developed on the basis of systematic reviews of the medical literature and formal judgments by an expert panel. The CQI study involved 439 quality indicators covering 30 clinical conditions and preventive care.28 The VHA project used the 348 quality indicators from the CQI study that were relevant to the care of male veterans, covering 26 clinical areas.26 The 236 quality indicators in the ACOVE study specifically targeted vulnerable older patients, covering 22 medical and geriatric conditions and crosscutting clinical areas.25 Examples of the quality indicators are presented in Table 1Table 1Examples of Quality Indicators Used in the Community Quality Index (CQI), the Veterans Health Administration (VHA), and the Assessing Care of Vulnerable Elders (ACOVE) Projects.. Information on medical care provided to the study patients was derived from medical records and supplemented by interviews with patients in the CQI and ACOVE studies about selected quality indicators for which the patient was judged to provide information that was more reliable than the medical records. Medical records were abstracted by nurses with previous experience in medical-record abstraction who also underwent rigorous training. Abstraction of data used to determine the satisfaction of quality indicators was uniform, as indicated by kappa statistics of 0.80 or higher.

Quality-of-care scores were calculated at the patient level as the percentage of recommended care processes received. All analyses were conducted at the patient level. Patients were eligible for various quality indicators, depending on their conditions. For example, a patient who had three conditions — diabetes, heart failure, and hypertension — might have been eligible for six diabetes indicators, four heart-failure indicators, and five hypertension indicators. If four, two, and three indicators, respectively, were satisfied, the patient's average quality score would be 60%.

Medical Conditions

The primary predictor variable in this study was the total number of identified conditions affecting each patient. We selected chronic conditions that require continuous management, and we studied both common and unique sets of conditions. The conditions common to patients across the three studies were depression, diabetes mellitus, heart failure, stroke, hypertension, coronary artery disease, osteoarthritis, chronic obstructive pulmonary disease, and atrial fibrillation. Conditions unique to patients in the ACOVE study were dementia, pressure ulcer, osteoporosis, urinary incontinence, and renal insufficiency. Conditions unique to patients in the CQI and VHA projects were benign prostatic hypertrophy, dyspepsia, asthma, colorectal cancer, and prostate cancer. Breast cancer was present only in the CQI cohort.

Statistical Analysis

Main Analysis

We first plotted the relationship between the number of conditions a patient had and the overall quality of care the patient received. After confirming the linear trend, we ran linear regression models at the patient level, using quality of care as the outcome variable and the number of conditions as the primary predictor variable. The coefficient of the number of conditions was used to estimate the increase in the quality of care associated with the addition of a coexisting condition.

There were at least two types of potential artifacts in the main statistical analysis. The first arose from the fact that patients were eligible for various sets of quality indicators (according to their medical conditions) and that the difficulty of delivering the care recommended in an indicator could vary.25 To adjust for this, we calculated an expected quality score, on the basis of population scores, for the quality indicators for which the patient was eligible.29 We subtracted the expected score from the patient's actual score to calculate a quality score adjusted for difficulty. We then examined the relationship between the adjusted quality score and the number of conditions the patient had.

A second potential artifact was that the same care processes satisfy quality indicators that target different conditions. For example, daily antiplatelet therapy is recommended both for patients with diabetes and for patients with coronary heart disease. Therefore, patients with both conditions are eligible for aspirin therapy twice. To control for this artifact, we counted multiple eligibilities for the same indicator only once in the score calculation.

Exploratory Analysis of Mechanisms of the Quality–Care Relationship

To explore potential mechanisms of the observed relationship between the number of conditions and the quality score, we tested the effect of three potentially contributing factors: demographic characteristics of patients, use of health care, and care provided by specialists. After adjusting for demographic characteristics and use of health care in the model, we examined the change in the slope of the regression curve for the quality of care and number of conditions. Quality scores for the ACOVE and CQI data were adjusted for age, sex, education level, annual income, self-reported health, and geographic characteristics (i.e., the two managed-care organizations in the ACOVE study and the 12 metropolitan areas in the CQI study). The CQI data were further adjusted for race and ethnic group and for type of health insurance. We did not adjust the ACOVE data for these variables, because the patients were predominantly white, and all were enrolled in a managed-care plan for seniors. All patients from the VHA project were male, and their other demographic data were limited; therefore, we adjusted only for age and geographic region (i.e., Veterans Integrated Service Network). The adjustment for the use of health care addressed the number of office visits in each of the three data sets and the number of hospitalizations in the CQI and ACOVE data sets.

Using the ACOVE data, we examined the effect of the involvement of specialists and the number of providers. Data on the specialty of providers were not collected in the CQI and VHA projects. We performed the first analysis by consecutively adding two variables to the linear-regression model of quality score and number of conditions: first, a binary variable indicating whether or not the patient received any specialist care, and second, the interaction term for the binary variable and the number of conditions. The interaction term was used to examine the difference in the relationship of quality score to the number of conditions between patients who were treated only by generalists and patients who received any care from specialists. We conducted the second analysis by adding data on the number of providers to the linear regression model adjusted for demographic characteristics.

All analyses were conducted with the use of Stata software, version 9.2. P values less than 0.05 were considered to indicate statistical significance.

Results

Patient Populations

Table 2Table 2Patient Characteristics, According to Cohort. describes the characteristics of the three populations of patients. The numbers of conditions ranged from zero to eight among patients in the ACOVE study and from zero to seven among patients in the CQI and VHA projects. Patients were eligible for a mean of 20, 16, and 19 quality indicators in the ACOVE, CQI, and VHA data sets, respectively. The mean quality scores were 55% in both the ACOVE and CQI cohorts and 67% in the VHA cohort.

Relationships between Quality Score and Number of Conditions

Figure 1Figure 1Relationship between Number of Chronic Conditions and Quality of Health Care in Each of the Three Cohorts. shows the relationship between the number of conditions and the quality of care received in each of the three cohorts. In general, as the number of conditions increased from zero to five, the quality-of-care scores also increased; small numbers of patients with six or seven conditions resulted in imprecision of those point estimates. The unadjusted linear regression analysis showed that each additional condition was associated with a 2.2% increase in the quality score (95% confidence interval [CI], 1.7 to 2.7) for the CQI cohort, 1.7% (95% CI, 1.1 to 2.4) for the ACOVE cohort, and 1.7% (95% CI, 0.7 to 2.8) for the VHA cohort. Figure 2Figure 2Effect of Adjustment for Measurement Artifacts on the Relationship between Number of Chronic Conditions and Quality Score. shows the effect of adjustment for two potential artifacts of measurement on the slope of the relationship between the quality of care and number of conditions. Since the effect was minimal, later analyses did not involve such adjustment.

Potential Mechanisms of the Quality–Condition Relationship

Figure 3Figure 3Effect of Adjustment for Characteristics of Patients and Use of Health Care on the Relationship between Number of Conditions and Quality Score. presents the effect of adjustment for characteristics of patients and use of health care. For the ACOVE and CQI cohorts, the relationship between the quality score and the number of conditions remained moderately positive after adjustment; in the VHA cohort, the adjusted slope was positive but not significantly different from a slope of zero (P=0.17). The adjustment for care provided by specialists and number of providers was possible only in the ACOVE data set. Among the 372 ACOVE patients who were eligible for 10,711 care processes, 233 saw at least one specialist for a condition for which there was a quality indicator. Addition of the binary variable indicating whether or not the patient received any care from a specialist did not change the relationship between the number of conditions and the quality score. The analysis including the interaction term between receipt of care from a specialist and number of conditions showed that the relationship between the number of conditions and the quality score was significantly smaller (but still positive) among patients who did not receive care from specialists than among those who did, although this difference was significant only in the unadjusted analysis (the change in the slope of the regression curve, 0.6 vs. 2.2 percentage points for the unadjusted analysis, P=0.02; 0.73 vs. 2.0 percentage points for the analysis adjusted for demographic characteristics, P=0.07; and 0.49 vs. 1.8 percentage points for the analysis adjusted for demographic characteristics and use of health care, P=0.08). The addition of the number of providers to the model adjusted for demographic characteristics minimally reduced the magnitude of the increase in the slope of the quality–condition curve (from 1.60 percentage points for each additional condition to 1.54 percentage points). Each additional provider involved was associated with an increase of 0.3 percentage point (P=0.39).

Discussion

Contrary to our expectations, we found that the percentage of care recommended in quality indicators that was delivered to each patient increased, rather than decreased, as a patient's number of chronic conditions increased. The fact that we found essentially the same relationship in three different data sets, using two different sets of quality indicators, increases the likelihood that this effect is real, rather than an artifact of any one particular study. This finding does not provide support for the argument that incentive programs based on quality indicators of care processes will necessarily penalize providers who provide care to patients with multiple conditions.

Unlike our study, previous studies that have examined the effect of coexisting conditions on the provision of necessary care processes have generally focused on single areas of care, such as preventive care, with mixed results. Redelmeier and colleagues30 reported finding a negative effect of the presence of diabetes on receipt of estrogen-replacement therapy, of pulmonary emphysema on the necessary use of lipid-lowering medications, and of psychotic syndromes (as identified by the use of haloperidol) on treatment for arthritis. Desai and colleagues31 found little difference in the care received for diabetes among veterans with mental disorders and those without. Heflin and collegues32 found an increased likelihood of undergoing a clinical breast examination, Papanicolaou smears, and fecal occult-blood testing among older patients with hypertension, whereas the likelihood of mammography was reduced among patients with hip fracture. They found no evidence that patients with other conditions, such as stroke and diabetes, had a reduced likelihood of undergoing four cancer-screening processes.

Although we had limited data on the mechanisms underlying the positive relationship between the quality score and the number of conditions, several of our analyses were informative. First, the increased use of health care by patients with more conditions explained some of the positive quality–condition relationship. In all three data sets, the slope of the curve was less after we adjusted for the use of health care than before adjustment. This effect was particularly prominent in the VHA data set, for which the slope was essentially flat after adjustment. This finding does provide support for the hypothesis that patients with more conditions receive higher-quality care than patients with fewer conditions, because they have more opportunities to receive care. Second, the data from the ACOVE study suggest that the involvement of specialists plays a modest role in the positive relationship between the number of conditions and the quality of care. The quality score for each additional condition increased more for patients who had seen a relevant specialist than for those who had not. This result is consistent with reports in the literature that specialists provide higher-quality care in their areas of specialty than do generalists.33-35 However, for patients who received only generalist care, the relationship between the quality score and the number of conditions remained positive. These data suggest that generalists can provide equivalent care to patients with complex conditions and to those with less complex conditions. A potential mechanism that we could not assess in our study, however, is the possibility that seeing a specialist is a marker for patients who advocate more effectively for the care they need.

Our study had several limitations. First, we used a simple count of conditions as the primary predictor variable. This variable is a crude measure of complexity, since clinicians do not view all coexisting conditions as equivalent. For example, they view depression as a more challenging coexisting condition than hypertension or osteoarthritis. Furthermore, our data do not take into account the severity of illness for any particular condition, such as severe diabetes as compared with mild diabetes. The data sets were, in general, too small to permit the examination of specific positive and negative effects on the quality of care processes for various combinations of conditions. Because we considered only conditions that had corresponding quality indicators, we underestimated the total disease burden. Our sets of quality indicators did not assess psychosocial issues, which may be an additional contributor to the difficulty in providing quality care. However, the sets were extensive, covering the most prevalent conditions.

Second, the quality score appeared to decrease for patients in the CQI and VHA cohorts who had seven conditions (five patients [<0.1%] and three patients [0.5%], respectively), although the small samples prevent us from making any conclusions for these patients. Future studies should focus on the quality of care provided to patients with a highly complex disease burden, although such patients are likely to account for a very small fraction of any provider's patients. Third, since our performance measures focused on technical quality of care (whether or not patients were offered recommended services), we cannot draw conclusions about the relationship between the number of conditions and the experience of the patient, the quality of communication between the patient and physician, or the outcomes of care. Finally, the CQI, ACOVE, and VHA projects measured quality with the use of a comprehensive set of care processes that were carefully constructed to account for a patient's detailed clinical status. Our results may not be generalizable to quality indicators based on outcomes or quality indicators that are less clinically detailed or that assess a smaller percentage of the care received.

In summary, contrary to expectations, we found that patients with more conditions that have corresponding quality indicators consistently received better technical quality of care for these conditions than did patients with fewer conditions. This finding suggests that comprehensive, clinically detailed sets of care processes received can be used to assess the quality of care without creating a disincentive for providers to avoid patients with the most prevalent chronic conditions.

Supported by the RAND Corporation and the National Primary Care Research and Development Centre, England.

No potential conflict of interest relevant to this article was reported.

Source Information

From Kyoto University, Kyoto, Japan (T.H.); University of California at Los Angeles (N.S.W.) and the Veterans Affairs Greater Los Angeles Healthcare System (C.F., S.M.A., P.G.S.) — both in Los Angeles; RAND Health, Santa Monica, CA (N.S.W., J.L.A., C.F., E.A.M., S.M.A., P.G.S.); National Primary Care Research and Development Centre, University of Manchester, Manchester, United Kingdom (M.R., D.R.); and the Veterans Affairs Ann Arbor Health Care System and the University of Michigan Department of Internal Medicine — both in Ann Arbor (E.A.K.).

Address reprint requests to Dr. Shekelle at the RAND Corporation, 1776 Main St., P.O. Box 2138, Santa Monica, CA 90407-2138, or at .

References

References

  1. 1

    Schuster MA, McGlynn EA, Brook RH. How good is the quality of health care in the United States? Milbank Q 1998;76:517-563
    CrossRef | Web of Science | Medline

  2. 2

    Jencks SF, Cuerdon T, Burwen DR, et al. Quality of medical care delivered to Medicare beneficiaries: a profile at state and national levels. JAMA 2000;284:1670-1676
    CrossRef | Web of Science | Medline

  3. 3

    Shekelle PG, MacLean CH, Morton SC, Wenger NS. Assessing care of vulnerable elders: methods for developing quality indicators. Ann Intern Med 2001;135:647-652
    Web of Science | Medline

  4. 4

    McGlynn EA, Asch SM, Adams J, et al. The quality of health care delivered to adults in the United States. N Engl J Med 2003;348:2635-2645
    Full Text | Web of Science | Medline

  5. 5

    Health Plan Employer Data and Information Set (HEDIS). Washington, DC: National Committee for Quality Assurance. (Accessed May 18, 2007, at http://www.ncqa.org/programs/hedis/.)

  6. 6

    Kizer KW, Demakis JG, Feussner JR. Reinventing VA health care: systematizing quality improvement and quality innovation. Med Care 2000;38:Suppl 1:I7-I16
    CrossRef | Medline

  7. 7

    Davies HT, Marshall MN. Public disclosure of performance data: does the public get what the public wants? Lancet 1999;353:1639-1640
    CrossRef | Web of Science | Medline

  8. 8

    Marshall MN, Shekelle PG, Leatherman S, Brook RH. The public release of performance data: what do we expect to gain? A review of the evidence. JAMA 2000;283:1866-1874
    CrossRef | Web of Science | Medline

  9. 9

    Epstein AM. Paying for performance in the United States and abroad. N Engl J Med 2006;355:406-408
    Full Text | Web of Science | Medline

  10. 10

    Christianson JB, Knutson DJ, Mazze RS. Physician pay-for-performance: implementation and research issues. J Gen Intern Med 2006;21:Suppl 2:S9-S13
    Web of Science | Medline

  11. 11

    Berenson RA, Horvath J. Confronting the barriers to chronic care management in Medicare. Health Aff (Millwood)2003;W3-37
    Medline

  12. 12

    Wolff JL, Starfield B, Anderson G. Prevalence, expenditures, and complications of multiple chronic conditions in the elderly. Arch Intern Med 2002;162:2269-2276
    CrossRef | Web of Science | Medline

  13. 13

    Forrest CB, Villagra VV, Pope JE. Managing the metric vs managing the patient: the physician's view of pay for performance. Am J Manag Care 2006;12:83-85
    Web of Science | Medline

  14. 14

    Mannion R, Davies H, Marshall M. Impact of star performance ratings in English acute hospital trusts. J Health Serv Res Policy 2005;10:18-24
    CrossRef | Medline

  15. 15

    Werner RM, Asch DA. The unintended consequences of publicly reporting quality information. JAMA 2005;293:1239-1244
    CrossRef | Web of Science | Medline

  16. 16

    Walter LC, Davidowitz NP, Heineken PA, Covinsky KE. Pitfalls of converting practice guidelines into quality measures: lessons learned from a VA performance measure. JAMA 2004;291:2466-2470
    CrossRef | Web of Science | Medline

  17. 17

    Shen Y. Selection incentives in a performance-based contracting system. Health Serv Res 2003;38:535-552
    CrossRef | Web of Science | Medline

  18. 18

    Ciechanowski PS, Katon WJ, Russo JE. Depression and diabetes: impact of depressive symptoms on adherence, function, and costs. Arch Intern Med 2000;160:3278-3285
    CrossRef | Web of Science | Medline

  19. 19

    Piette JD, Kerr EA. The impact of comorbid chronic conditions on diabetes care. Diabetes Care 2006;29:725-731
    CrossRef | Web of Science | Medline

  20. 20

    Yarnall KS, Pollak KI, Ostbye T, Krause KM, Michener JL. Primary care: is there enough time for prevention? Am J Public Health 2003;93:635-641
    CrossRef | Web of Science | Medline

  21. 21

    Ostbye T, Yarnall KS, Krause KM, Pollak KI, Gradison M, Michener JL. Is there time for management of patients with chronic diseases in primary care? Ann Fam Med 2005;3:209-214
    CrossRef | Web of Science | Medline

  22. 22

    Davies HT, Washington AE, Bindman AB. Health care report cards: implications for vulnerable patient groups and the organizations providing them care. J Health Polit Policy Law 2002;27:379-399
    CrossRef | Web of Science | Medline

  23. 23

    Boyd CM, Darer J, Boult C, Fried LP, Boult L, Wu AW. Clinical practice guidelines and quality of care for older patients with multiple comorbid diseases: implications for pay for performance. JAMA 2005;294:716-724
    CrossRef | Web of Science | Medline

  24. 24

    Wenger NS, Shekelle PG. Assessing care of vulnerable elders: ACOVE project overview. Ann Intern Med 2001;135:642-646
    Web of Science | Medline

  25. 25

    Wenger NS, Solomon DH, Roth CP, et al. The quality of medical care provided to vulnerable community-dwelling older patients. Ann Intern Med 2003;139:740-747
    Web of Science | Medline

  26. 26

    Asch SM, McGlynn EA, Hogan MM, et al. Comparison of quality of care for patients in the Veterans Health Administration and patients in a national sample. Ann Intern Med 2004;141:938-945
    Web of Science | Medline

  27. 27

    Saliba D, Elliott M, Rubenstein LZ, et al. The Vulnerable Elders Survey: a tool for identifying vulnerable older people in the community. J Am Geriatr Soc 2001;49:1691-1699
    CrossRef | Web of Science | Medline

  28. 28

    The quality of health care delivered to adults in the United States: Appendix. Santa Monica, CA: RAND, 2006. (Accessed May 18, 2007, at http://www.rand.org/pubs/working_papers/WR174-1/.)

  29. 29

    Min LC, Reuben DB, MacLean CH, et al. Predictors of overall quality of care provided to vulnerable older people. J Am Geriatr Soc 2005;53:1705-1711
    CrossRef | Web of Science | Medline

  30. 30

    Redelmeier DA, Tan SH, Booth GL. The treatment of unrelated disorders in patients with chronic medical diseases. N Engl J Med 1998;338:1516-1520
    Full Text | Web of Science | Medline

  31. 31

    Desai MM, Rosenheck RA, Druss BG, Perlin JB. Mental disorders and quality of diabetes care in the Veterans Health Administration. Am J Psychiatry 2002;159:1584-1590
    CrossRef | Web of Science | Medline

  32. 32

    Heflin MT, Oddone EZ, Pieper CF, Burchett BM, Cohen HJ. The effect of comorbid illness on receipt of cancer screening by older people. J Am Geriatr Soc 2002;50:1651-1658
    CrossRef | Web of Science | Medline

  33. 33

    Diette GB, Skinner EA, Nguyen TT, Markson L, Clark BD, Wu AW. Comparison of quality of care by specialist and generalist physicians as usual source of asthma care for children. Pediatrics 2001;108:432-437
    CrossRef | Web of Science | Medline

  34. 34

    Donohoe MT. Comparing generalist and specialty care: discrepancies, deficiencies, and excesses. Arch Intern Med 1998;158:1596-1608
    CrossRef | Web of Science | Medline

  35. 35

    Harrold LR, Field TS, Gurwitz JH. Knowledge, patterns of care, and outcomes of care for generalists and specialists. J Gen Intern Med 1999;14:499-511
    CrossRef | Web of Science | Medline

Citing Articles (44)

Citing Articles

  1. 1

    M. Askari, P. C. Wierenga, S. Eslami, S. Medlock, S. E. De Rooij, A. Abu-Hanna. (2012) Studies pertaining to the ACOVE quality criteria: a systematic review. International Journal for Quality in Health Care 24:1, 80-87
    CrossRef

  2. 2

    Nancy J. Wei, Richard W. Grant, David M. Nathan, Deborah J. Wexler. (2012) Effect of Hospital Admission on Glycemic Control One Year after Discharge. Endocrine Practice 1:-1, 1-22
    CrossRef

  3. 3

    L. G. Glynn, J. M. Valderas, P. Healy, E. Burke, J. Newell, P. Gillespie, A. W. Murphy. (2011) The prevalence of multimorbidity in primary care and its effect on health care utilization and cost. Family Practice 28:5, 516-523
    CrossRef

  4. 4

    Alessandra Marengoni, Sara Angleman, René Melis, Francesca Mangialasche, Anita Karp, Annika Garmen, Bettina Meinow, Laura Fratiglioni. (2011) Aging with multimorbidity: A systematic review of the literature. Ageing Research Reviews 10:4, 430-439
    CrossRef

  5. 5

    Salim S. Virani, LeChauncy D. Woodard, Cassie R. Landrum, Kenneth Pietz, Degang Wang, Christie M. Ballantyne, Laura A. Petersen. (2011) Institutional, provider, and patient correlates of low-density lipoprotein and non–high-density lipoprotein cholesterol goal attainment according to the Adult Treatment Panel III guidelines. American Heart Journal 161:6, 1140-1146
    CrossRef

  6. 6

    Elizabeth A. Bayliss, Patrick J. Blatchford, Sophia R. Newcomer, John F. Steiner, Diane L. Fairclough. (2011) The Effect of Incident Cancer, Depression and Pulmonary Disease Exacerbations on Type 2 Diabetes Control. Journal of General Internal Medicine 26:6, 575-581
    CrossRef

  7. 7

    A. A. Laverty, A. Bottle, A. Majeed, C. Millett. (2011) Blood pressure monitoring and control by cardiovascular disease status in UK primary care: 10 year retrospective cohort study 1998-2007. Journal of Public Health 33:2, 302-309
    CrossRef

  8. 8

    Dominik Ose, Tobias Freund, Elisabeth Urban, Cornelia Ursula Kunz, Joachim Szecsenyi, Antje Miksch. (2011) Comorbidity and patient-reported quality of care: an evaluation of the primary care based German disease management program for type 2 diabetes. Journal of Public Health
    CrossRef

  9. 9

    Christie M. Bartels, Amy J. H. Kind, Christine Everett, Matthew Mell, Patrick McBride, Maureen Smith. (2011) Low frequency of primary lipid screening among Medicare patients with rheumatoid arthritis. Arthritis & Rheumatism 63:5, 1221-1230
    CrossRef

  10. 10

    Cynthia M. Boyd, Bruce Leff, Jennifer L. Wolff, Qilu Yu, Jing Zhou, Cynthia Rand, Carlos O. Weiss. (2011) Informing Clinical Practice Guideline Development and Implementation: Prevalence of Coexisting Conditions Among Adults with Coronary Heart Disease. Journal of the American Geriatrics Society 59:5, 797-805
    CrossRef

  11. 11

    C. Diederichs, K. Berger, D. B. Bartels. (2011) The Measurement of Multiple Chronic Diseases--A Systematic Review on Existing Multimorbidity Indices. The Journals of Gerontology Series A: Biological Sciences and Medical Sciences 66A:3, 301-311
    CrossRef

  12. 12

    Clare Liddy, Jatinderpreet Singh, William Hogg, Simone Dahrouge, Monica Taljaard. (2011) Comparison of primary care models in the prevention of cardiovascular disease - a cross sectional study. BMC Family Practice 12:1, 114
    CrossRef

  13. 13

    Lillian C. Min, David B. Reuben, Emmett Keeler, David A. Ganz, Constance H. Fung, Paul Shekelle, Carol P. Roth, Neil S. Wenger. (2011) Is Patient-Perceived Severity of a Geriatric Condition Related to Better Quality of Care?. Medical Care 49:1, 101-107
    CrossRef

  14. 14

    Julie P. W. Bynum, Elliott S. Fisher, Yunjie Song, Jonathan Skinner, Amitabh Chandra. (2010) Measuring Racial Disparities in the Quality of Ambulatory Diabetes Care. Medical Care 48:12, 1057-1063
    CrossRef

  15. 15

    David Katerndahl, Michael Parchman, Robert Wood. (2010) Trends in the perceived complexity of primary health care: a secondary analysis. Journal of Evaluation in Clinical Practice 16:5, 1002-1008
    CrossRef

  16. 16

    Vineet M. Arora, Melissa Fish, Anirban Basu, Jared Olson, Colleen Plein, Kalpana Suresh, Greg Sachs, David O. Meltzer. (2010) Relationship Between Quality of Care of Hospitalized Vulnerable Elders and Postdischarge Mortality. Journal of the American Geriatrics Society 58:9, 1642-1648
    CrossRef

  17. 17

    Shauna T. Linn, Jack M. Guralnik, Kushang V. Patel. (2010) Disparities in Influenza Vaccine Coverage in the United States, 2008. Journal of the American Geriatrics Society 58:7, 1333-1340
    CrossRef

  18. 18

    Marije Bosch, Michel Wensing, J. Carel Bakx, Trudy Van Der Weijden, Arno W. Hoes, Richard P.T.M. Grol. (2010) Current treatment of chronic heart failure in primary care; still room for improvement. Journal of Evaluation in Clinical Practiceno-no
    CrossRef

  19. 19

    Norman K. Hollenberg. (2010) Medical Complexity and Hypertension Management. Current Hypertension Reports 12:2, 59-60
    CrossRef

  20. 20

    Y. Zhang, A. Vitry, E. Roughead, P. Ryan, A. Gilbert. (2010) Co-morbidity and the utilization of health care for Australian veterans with diabetes. Diabetic Medicine 27:1, 65-71
    CrossRef

  21. 21

    Sumeet K. Asrani, Paula Buchanan, Brett Pinsky, Lisa Rocca Rey, Mark Schnitzler, Fasiha Kanwal. (2010) Lack of Association Between Hepatitis C Infection and Chronic Kidney Disease. Clinical Gastroenterology and Hepatology 8:1, 79-84
    CrossRef

  22. 22

    Christine T. Cigolle, Caroline S. Blaum, Jeffrey B. Halter. (2009) Diabetes and Cardiovascular Disease Prevention in Older Adults. Clinics in Geriatric Medicine 25:4, 607-641
    CrossRef

  23. 23

    Richard H. Chapman, Allison A. Petrilla, Lance Berman, Joshua S. Benner, Simon S.K. Tang. (2009) Are High-Risk Hypertensive Patients being Prescribed Concomitant Statin Therapy?. American Journal Cardiovascular Drugs 9:5, 299-308
    CrossRef

  24. 24

    Crystal W. Cené, Debra Roter, Kathryn A. Carson, Edgar R. Miller, Lisa A. Cooper. (2009) The Effect of Patient Race and Blood Pressure Control on Patient-Physician Communication. Journal of General Internal Medicine 24:9, 1057-1064
    CrossRef

  25. 25

    Vineet M. Arora, Colleen Plein, Stuart Chen, Juned Siddique, Greg A. Sachs, David O. Meltzer. (2009) Relationship Between Quality of Care and Functional Decline in Hospitalized Vulnerable Elders. Medical Care 47:8, 895-901
    CrossRef

  26. 26

    Irina Yermilov, Marcia L. McGory, Paul W. Shekelle, Clifford Y. Ko, Melinda A. Maggard. (2009) Appropriateness Criteria for Bariatric Surgery: Beyond the NIH Guidelines. Obesity 17:8, 1521-1527
    CrossRef

  27. 27

    Patricia S. Keenan, Marc N. Elliott, Paul D. Cleary, Alan M. Zaslavsky, Bruce E. Landon. (2009) Quality Assessments by Sick and Healthy Beneficiaries in Traditional Medicare and Medicare Managed Care. Medical Care 47:8, 882-888
    CrossRef

  28. 28

    A. J. Mitchell, D. Malone, C. C. Doebbeling. (2009) Quality of medical care for people with and without comorbid mental illness and substance misuse: systematic review of comparative studies. The British Journal of Psychiatry 194:6, 491-499
    CrossRef

  29. 29

    Robin E. Clark, Sharada Weir, Rebecca A. Ouellette, Jianying Zhang, Jeffrey D. Baxter. (2009) Beyond Health Plans. Medical Care 47:5, 545-552
    CrossRef

  30. 30

    Douglas A. Conrad, Lisa Perry. (2009) Quality-Based Financial Incentives in Health Care: Can We Improve Quality by Paying for It?. Annual Review of Public Health 30:1, 357-371
    CrossRef

  31. 31

    Pearl G. Lee, Christine Cigolle, Caroline Blaum. (2009) The Co-Occurrence of Chronic Diseases and Geriatric Syndromes: The Health and Retirement Study. Journal of the American Geriatrics Society 57:3, 511-516
    CrossRef

  32. 32

    C. Seth Landefeld. (2009) Pragmatic Approaches that Improve Care for Geriatric Conditions: Balancing the Promise and the Peril of Quality Indicators. Journal of the American Geriatrics Society 57:3, 556-558
    CrossRef

  33. 33

    Lenny Lopez, E. Francis Cook, Mark S. Horng, LeRoi S. Hicks. (2009) Lifestyle Modification Counseling for Hypertensive Patients: Results From the National Health and Nutrition Examination Survey 1999–2004. American Journal of Hypertension 22:3, 325-331
    CrossRef

  34. 34

    Laurence F. McMahon, Michele Heisler. (2008) Looking for Quality under the Lamppost. Journal of General Internal Medicine 23:11, 1923-1925
    CrossRef

  35. 35

    Rachel M. Werner, Virginia W. Chang. (2008) The Relationship Between Measured Performance and Satisfaction with Care Among Clinically Complex Patients. Journal of General Internal Medicine 23:11, 1729-1735
    CrossRef

  36. 36

    Elizabeth A. Phelan, Scott Genshaft, Barbara Williams, James P. LoGerfo, Edward H. Wagner. (2008) A Comparison of How Generalists and Fellowship-Trained Geriatricians Provide âGeriatricâ Care. Journal of the American Geriatrics Society 56:10, 1807-1811
    CrossRef

  37. 37

    E. A Bayliss, A. E Edwards, J. F Steiner, D. S Main. (2008) Processes of care desired by elderly patients with multimorbidities. Family Practice 25:4, 287-293
    CrossRef

  38. 38

    Tara Lagu, Mark G. Weiner, Christopher S. Hollenbeak, Susan Eachus, Craig S. Roberts, J. Sanford Schwartz, Barbara J. Turner. (2008) The Impact of Concordant and Discordant Conditions on the Quality of Care for Hyperlipidemia. Journal of General Internal Medicine 23:8, 1208-1213
    CrossRef

  39. 39

    Constance H. Fung, Claude M. Setodji, Fuan-Yue Kung, Joan Keesey, Steven M. Asch, John Adams, Elizabeth A. McGlynn. (2008) The Relationship Between Multimorbidity and Patients’ Ratings of Communication. Journal of General Internal Medicine 23:6, 788-793
    CrossRef

  40. 40

    Nicholas Kontos, Oliver Freudenreich, John Querques. (2008) Ownership, responsibility and hospital care: lessons for the consultation psychiatrist. General Hospital Psychiatry 30:3, 257-262
    CrossRef

  41. 41

    Jinoos Yazdany, Catherine H MacLean. (2008) Quality of care in the rheumatic diseases: current status and future directions. Current Opinion in Rheumatology 20:2, 159-166
    CrossRef

  42. 42

    Samuel C Durso. (2007) Prioritizing care for older adults with multiple comorbidities: working in the ‘zone of complexity’. Aging Health 3:6, 715-721
    CrossRef

  43. 43

    Neil S. Wenger. (2007) Comorbidity and Quality of Care: Clarification From Author. Medical Care 45:12, 1233
    CrossRef

  44. 44

    (2007) Number of Medical Conditions and Quality of Care. New England Journal of Medicine 357:13, 1350-1351
    Full Text

Letters