Aims: Although many patients with heart failure have incomplete adherence to prescribed medications, predisposing factors remain unclear. This analysis investigates factors associated with adherence, with particular emphasis on age and sex.
Methods and results: A multivariable regression analysis of 7599 heart failure patients from the CHARM trial was done to evaluate factors associated with adherence. Adherence was measured as the proportion of time patients took more than 80% of study medication. The mean age was 66 years (SD 11) and 31.5% (n = 2400) were women. Women were slightly less adherent than men (87.3 vs. 89.8%, P = 0.002), even in adjusted, multivariable models (treatment, P = 0.006; placebo P = 0.004; and overall P < 0.001). However, all-cause mortality was lower in women (21.5%) than in men (25.3%) (adjusted hazard ratio, 0.77; 95% CI, 0.69-0.86; P < 0.001), but patients with a low adherence regardless of sex had a higher mortality. Age, severity of heart failure, number of medications, and smoking status were not associated with adherence.
Conclusion: Women, particularly those <75 years of age, were less likely to be adherent in this large sample of patients with symptomatic heart failure. Understanding factors associated with adherence may provide opportunities for intervention.