Correspondence

Insurance Copayments and Delays in Seeking Emergency Care

N Engl J Med 1997; 337:1247-1248October 23, 1997

Article

To the Editor:

Dr. Magid and colleagues (June 12 issue)1 provide interesting data on the correlates of delays in seeking treatment among patients with acute myocardial infarction. Because they studied only one health maintenance organization (HMO), the authors are appropriately circumspect about generalizing the observed nonassociation between cost sharing and treatment delay to other HMOs and to low-income populations at risk. However, the report and Dr. Selby's editorial2 neglect to discuss an important limitation to internal validity that should have tempered their conclusion that “in this HMO, the requirement of modest, fixed copayments for emergency services did not lead to delays in seeking treatment for myocardial infarction.”1 The cross-sectional, “post-only-with-comparison-group” design is one of the weaker quasi-experimental designs for measuring the impact of a policy.3 The absence of base-line observations makes it impossible to know whether for the population who made the copayment the delay was longer, shorter, or the same before the policy was implemented.

Measuring the impact of a policy in a valid way requires measuring change. The equivalence of the lengths of the delay between the copayment and no-copayment populations after the policy was implemented does not rule out the possibility that members of the employer groups instituting copayments had shorter delays before cost sharing, which increased to the level of the unexposed population after copayments were introduced. Moreover, the noncomparability of the two populations with respect to age, calendar year, and socioeconomic status may signal the existence of such unmeasured differences. Selby et al. used a stronger “pre–post-with-comparison-group” design to measure changes in emergency department use after the introduction of copayments.4 After controlling for sizable base-line differences between the copayment and control groups, they found that copayments did reduce emergency department use for diagnoses categorized as “often an emergency.”

Stephen B. Soumerai, Sc.D.
Harvard Medical School, Boston, MA 02115

Dennis Ross-Degnan, Sc.D.
Harvard Pilgrim Health Care, Boston, MA 02215

4 References

1. 1

   Magid DJ, Koepsell TD, Every NR, et al. Absence of association between insurance copayments and delays in seeking emergency care among patients with myocardial infarction. N Engl J Med 1997;336:1722-1729
   Full Text | Web of Science | Medline

2. 2

   Selby JV. Cost sharing in the emergency department -- is it safe? Is it needed? N Engl J Med 1997;336:1750-1751
   Full Text | Web of Science | Medline

3. 3

   Cook TD, Campbell DT. Quasi-experimentation: design and analysis issues for field settings. Boston: Houghton Mifflin, 1979.
   

4. 4

   Selby JV, Fireman BH, Swain BE. Effect of a copayment on use of the emergency department in a health maintenance organization. N Engl J Med 1996;334:635-641
   Full Text | Web of Science | Medline

To the Editor:

I wondered whether Magid et al. counted the patients who actually paid the copayment. Managed-care plans usually waive the copayment for members who are admitted to the hospital from the emergency room, but expect it to be paid by members who are discharged from the emergency room without being admitted to the hospital. When I was medical director of a large managed-care plan in New York, I was struck by the behavior of many members of very modest means who went to emergency rooms several nights in a row. On inquiring, I found that very few members had paid the amount in question. Many hospitals regard the copayment as an insignificant source of income and do not put many resources into collecting it. It was clear that the copayment of $25 had no effect on members' behavior, because they never had to pay it. Few clerks were instructed to collect it at the time, and the members consistently ignored the follow-up bills.

Judith M. Taylor, M.D.
611 Ridge Rd., Tiburon, CA 94920

Author/Editor Response

The authors reply:

To the Editor: We appreciate the comments of Drs. Soumerai and Ross-Degnan. Unfortunately, our data did not allow us to conduct a “pre–post” analysis. We agree that there is a theoretical possibility that bias may have been introduced by unmeasured differences between the copayment and no-copayment groups. However, we found that the copayment and no-copayment groups were similar with regard to most of the factors potentially related to delays. In addition, we found that adjusting for known differences in demographic, socioeconomic, and clinical characteristics had little impact on our findings. Drs. Soumerai and Ross-Degnan also commented on the study by Selby et al.,1 but neglected to mention that in that study the investigators found that copayments did not reduce the use of emergency departments by patients with conditions such as myocardial infarction, which were classified as “always an emergency.”

Dr. Taylor notes that copayments may have little effect on patients' behavior if they never have to pay it. The fact that studies conducted at Group Health Cooperative and in other health plans have consistently shown that cost sharing reduces the use of medical services suggests that as a rule members do not ignore the copayment in the belief that they will not have to pay it.1-5

David J. Magid, M.D., M.P.H.
Colorado Permanente Medical Group, Denver, CO 80231

Thomas D. Koepsell, M.D., M.P.H.
University of Washington School of Medicine, Seattle, WA 98105

Edward H. Wagner, M.D., M.P.H.
Group Health Cooperative of Puget Sound, Seattle, WA 98101

W. Douglas Weaver, M.D.
Henry Ford Health System, Detroit, MI 48202

5 References

1. 1

   Selby JV, Fireman BH, Swain BE. Effect of a copayment on use of the emergency department in a health maintenance organization. N Engl J Med 1996;334:635-641
   Full Text | Web of Science | Medline

2. 2

   O'Grady KF, Manning WG, Newhouse JP, Brook RH. The impact of cost sharing on emergency department use. N Engl J Med 1985;313:484-490
   Full Text | Web of Science | Medline

3. 3

   Lohr KN, Brook RH, Kamberg CJ, et al. Use of medical care in the Rand Health Insurance Experiment: diagnosis- and service-specific analyses in a randomized controlled trial. Med Care 1986;24:Suppl:S31-S38
   CrossRef

4. 4

   Manning WG, Newhouse JP, Duan N, et al. Health insurance and the demand for medical care: evidence from a randomized experiment. Am Econ Rev 1987;77:251-277
   Web of Science | Medline

5. 5

   Cherkin DC, Grothaus L, Wagner EH. The effect of office visit copayments on utilization in a health maintenance organization. Med Care 1989;27:669-679[Erratum, Med Care 1989;27:1036-45.]
   CrossRef | Web of Science

Citing Articles (1)

Citing Articles

1. 1

   Joshua H. Sarver, Rita K. Cydulka, David W. Baker. (2002) Usual Source of Care and Nonurgent Emergency Department Use. Academic Emergency Medicine 9:9, 916-923
   CrossRef