Objective: To examine the relationship between adherence to a medical regimen and mortality following a myocardial infarction in women.
Design: Analysis of the female cohort entered into a randomized double-blind multicenter trial.
Setting: National Heart, Lung, and Blood Institute beta-Blocker Heart Attack Trial.
Participants: The 602 women, aged 30 to 69 years, enrolled in the beta-Blocker Heart Attack Trial.
Intervention: Random assignment to propranolol hydrochloride or placebo 5 to 21 days following a myocardial infarction.
Measurements: Adherence for each patient was calculated as the mean of all quarterly adherence estimates during the course of the trial (median follow-up, 26 months). Adherence was classified as good (taking > or = 75% of medication) or poor (taking < 75% of medication). The end point was death from all causes occurring at any time during the trial, adjusted for treatment category and other clinical and sociodemographic features.
Results: Adherence data were available on 505 women, of whom 32 (6.3%) died. Death occurred in 13.6% of poor adherers compared with 5.6% of good adherers (relative risk, 2.4; 95% confidence interval, 1.1 to 5.6). The effect of adherence on mortality remained undiminished after adjustment for treatment category (propranolol or placebo), age, severity of myocardial infarction, congestive heart failure, smoking history, marital status, educational level, and race (adjusted relative risk of death for poor adherers, 2.5 to 3.0; P < or = .02).
Conclusions: The independent effect of adherence on mortality following a myocardial infarction in women is clinically substantial, statistically significant, and similar in magnitude to that reported earlier for men.