Association between statin intensity and adherence, and MACE in post-STEMI patients: A cohort study

Statins are among secondary preventive cardiovascular medications that adherence is critical to their effectiveness. Although, the management of cardiovascular diseases emphasize both intensity and patient adherence, observations show that statin adherence and intensity is not adequate. This study aimed to measure statin adherence and intensity in post-ST elevated myocardial infarction patients and its association with major adverse cardiovascular events (MACE).

Of 867 patients in the ST-elevated myocardial infarction cohort study in Isfahan, 549 individuals had data on the intensity of statin therapy. 455 of these patients tended to fill out the adherence questionnaire. Morisky Medication Adherence questionnaire and a checklist consisting potential adherence, and intensity-associated factors were filled out.

In the age group of 50-70 years, increasing age (P = 0.014), receiving physician's support on the consequences of statin discontinuation (P = 0.019), taking lower number of medications (P = 0.045) were significantly associated with statin adherence. Besides, the experience of side effects (P = 0.028) and depressed mood (P ≤ 0.0001) were negatively associated with adherence. None of the measured factors were associated with statin intensity. Statin adherence and statin intensity independently affect MACE, such that even after full adjustment, the chance of experiencing MACE increases 8% (95% CI = 1.02, 1.20) for low-statin adherents and 12% (1.04, 1.28) for patients on non-high statin intensity.

Statins have a significant role in the prediction of MACE, based on their intensity and adherence. Educational support from the physician, considering patients' mood and number of medications could improve patients' adherence.