Medication adherence and its determinants in patients after myocardial infarction.

Non-adherence to prescribed medication is a serious limitation of long-term treatment in patients after myocardial infarction (MI), which can be associated with medical, social and economical consequences. Improvement of medication adherence has been shown to be a challenge for healthcare providers. The aim of this study was to evaluate changes in medication adherence and variability of adherence determinants during follow-up in patients after MI. A single-center, cohort observational study was conducted in 225 post-MI patients treated with primary coronary intervention (PCI) (27% women and 73% men) aged 30-91 years. Adherence was defined as availability of evaluated drugs within 1-year after discharge from hospital, based on completed prescriptions data obtained from the National Health Fund. The analysis of therapeutic plan realization (adherence to medication prescribed at discharge from hospital) embraced only reimbursed drugs: ACEIs (ramipril, perindopril), P2Y12 receptor inhibitors (clopidogrel) and statins (atorvastatin, simvastatin, rosuvastatin). Sufficient adherence was defined as ≥ 80%. During 1-year follow-up, adherence for all three drug classes was 64 ± 25%, with 67 ± 32% for ACEIs, 62 ± 34% for P2Y12 receptor inhibitor and 64 ± 32% for statins. A gradual decline in adherence was observed from 65% ± 26% in the first quarter of follow-up to 51% ± 34% in the last quarter of follow-up (p < 0.00001). Sufficient adherence for all drugs classes was found only in 29% of patients throughout the whole follow-up period (44% for ACEI, 36% for P2Y12 receptor inhibitor and 41% for statins). According to a multivariate analysis, age, prior CABG, level of education, place of residence, economic status and marital status were independent predictors of drug adherence. Whereas patients > 65 years and having a history of prior CABG more often had an insufficient adherence to drugs, married and hypertensive patients, city inhabitants and patients with higher education tended to have a sufficient drug adherence. Adherence to pharmacotherapy after myocardial infarction decreases over time in a similar manner for all pivotal groups of drugs prescribed after MI. A number of socioeconomic and clinical factors have been identified to affect medication adherence over time.