Influence of sex, age and race on coronary and heart failure events in patients with diabetes and post-acute coronary syndrome

Background: Women, older patients and non-White ethnic groups experience a substantial proportion of acute coronary syndromes (ACS), although they have been historically underrepresented in ACS randomized clinical trials (RCTs). To assess the influence of sex, age and race on major adverse cardiovascular events (MACE) and on heart failure events, we studied patients with type 2 diabetes in a large post-ACS trial (EXAMINE).

Methods: Differences in baseline characteristics and the respective composite endpoint of cardiovascular death, nonfatal myocardial infarction, or nonfatal stroke (MACE) and cardiovascular death or heart failure hospitalization (HF events) were evaluated by subgroups in a cohort of post-ACS patients with diabetes, using unadjusted and adjusted Cox regression modelling.

Results: The EXAMINE trial enrolled 5380 patients with 35% aged > 65, 32% female and 27% non-White. The risk of MACE was higher in non-White compared to White patients after adjustment for potential confounding (HR = 1.35; 95% CI 1.04-1.75), but there were no significant differences by sex and age (HR = 1.03; 95% CI 0.87-1.22 for women; HR = 1.14; 95% CI 0.96-1.35 for patients ≥ 65 years). The risk of HF events was higher in non-White patients (HR = 1.56; 95% CI 1.13-2.14), and in patients aged > 65 (HR = 1.33; 95% CI 1.07-1.66) and nominally so in women (HR = 1.23; 95% CI 0.99-1.52). The additive risk of each demographic factor (women, older age and non-White race) was greater for HF events in comparison with MACE. Moreover, non-White elderly patients consistently had poorer prognosis regardless of sex.

Conclusions: Older adults, women and non-White patients with diabetes who are post-ACS are often underrepresented in RCTs. The risk for HF events was higher in older and non-White patients, with a trend towards significance in women, whereas only non-White patients (and not women and older patients) were at higher risk for MACE. Future trials should enrich enrollment of these persons at risk.