Intervening in depression and/or low perceived social support within 28 days after myocardial infarction (MI) in the Enhancing Recovery in Coronary Heart Disease (ENRICHD) clinical trial did not increase event-free survival. The purpose of the present investigation was to conduct post hoc analyses on sex and ethnic minority subgroups to assess whether any treatment subgroup is at reduced or increased risk of greater morbidity/mortality.
The 2481 patients with MI (973 white men, 424 minority men, 674 white women, 410 minority women) who had major or minor depression and/or low perceived social support were randomly allocated to usual medical care or cognitive behavior therapy. Total mortality or recurrent nonfatal MI (ENRICHD primary endpoint) and cardiac mortality or recurrent nonfatal MI (secondary endpoint) were analyzed as composite endpoints by group for time to first event using Cox proportional hazards regression.
There was a trend in the direction of treatment efficacy for white men for the primary endpoint (hazard ratio [HR], 0.80; 95% confidence interval, 0.61–1.05; p = .10) and a significant (p < .006, Bonferroni corrected) effect for the secondary endpoint (HR, 0.63; 95% CI, 0.46–0.87; p = .004). In contrast, the HRs for each of the other three subgroups were nonsignificant. The magnitude of differences in treatment effects between white men and the other subgroups remained significant for the secondary endpoint (p =.04) after adjustment for age, education, living alone, antidepressant use, comorbidity score, cardiac catheterization, ejection fraction, history of hypertension, and major depression.
White men, but not other subgroups, may have benefited from the ENRICHD intervention, suggesting that future studies need to attend to issues of treatment design and delivery that may have prevented benefit among sex and ethnic subgroups other than white men.