Aspirin treatment after myocardial infarction: are health maintenance organization members, women, and the elderly undertreated?

In April 1996, we surveyed 539 patients who had suffered a myocardial infarction in 1995 to determine whether the prescription and use of aspirin after myocardial infarction differs by patient age, sex, and type of health insurance. Patients who were insured through one of four health maintenance organizations in major metropolitan areas or by an indemnity plan in 40 states completed the survey. Among the 502 patients with no contraindications to use, 93.8% were prescribed aspirin. Among patients with a prescription and no subsequent contraindications to use, 96.4% were taking aspirin when surveyed. Among aspirin users, 96.5% reported taking aspirin daily. Controlling for other characteristics, 75-year-old patients were 5 percentage points less likely to receive a prescription for aspirin than were 50-year-old patients (P = 0.05). Although not significant at conventional levels, point estimates revealed a prescription rate for women that was 6 percentage points higher than that for men (P = 0.054) and a rate for health maintenance organization members that was 4 percentage points lower than that for patients with indemnity insurance (P = 0.10). Aspirin use was lower among older patients (P = 0.02) but did not differ by gender or type of insurance plan. Health maintenance organization members were just as likely to receive a prescription from a specialist as were those with indemnity insurance (P = 0.92). Based on these results, the rate of aspirin treatment after myocardial infarction may be much higher than previous studies indicate. Concerns that managed care patients and women may be undertreated are not supported by our findings. Although older patients are at risk for undertreatment, this risk is low. Once aspirin is prescribed, selfreported patient compliance with a daily regimen of aspirin is high.