Copayment by the patient has been shown to reduce the number of visits to the emergency department by 20 to 40 percent. It is not known, however, whether copayment delays care for truly urgent conditions, such as acute myocardial infarction. Magid and colleagues evaluated the interval between the onset of symptoms of myocardial infarction and arrival at the hospital to determine whether copayment for emergency services is associated with a delay in seeking care.

The Group Health Cooperative of Puget Sound is a prepaid health plan with more than 500,000 enrollees. From 1989 through 1994, a total of 1,523 patients with myocardial infarction were admitted to one of 19 hospitals participating in the Myocardial Infarction Triage and Intervention Project. Copayment status was known for 1,450 of these patients. The time from the onset of symptoms until hospital arrival was known for 1,331 (91.8 percent) of the 1,450 patients. These patients were enrolled in the study.

A total of 602 patients (45.2 percent) were enrolled in health care plans that required copayment for emergency services, and 729 patients (54.8 percent) were in plans that did not require copayment. Of the patients enrolled in plans that required copayment, 308 (51.2 percent) paid $25 for an emergency department visit, 289 (48.0 percent) paid $50 and five (0.8 percent) paid $100 for an emergency department visit.

Most of the patients younger than 65 years of age were enrolled in plans that required copayment. Fewer plans in which older patients were enrolled required copayment for emergency services.

The age-adjusted median time until arrival at the hospital was 136 minutes for patients with no copayment requirement, compared with 135 minutes for those with a $25 copayment and 138 minutes for those with a copayment of $50 or more. In the subgroup of 449 patients who had a cardiac arrest, no association between copayment status and the occurrence of cardiac arrest was demonstrated. The proportion of patients with plans that required copayment was similar in the group with cardiac arrest and in the group without cardiac arrest (48.3 percent and 49.5 percent, respectively). No statistically significant differences were noted in in-hospital case fatality rates or in long-term survival during the follow-up period (mean: 2.1 years).

The authors conclude that copayments for emergency services were not associated with a delay in seeking emergency treatment of myocardial infarction in the population they studied. Although no significant association was noted between income and the effect of copayment, the authors note that this lack of an association should be viewed with caution for two reasons: they used census-block data as a proxy for family income, and few indigent people are enrolled in the Group Health Cooperative of Puget Sound.