Socio-demographic differences in adherence to evidence-based drug therapy after hospital discharge from acute myocardial infarction: a population-based cohort study in Rome, Italy

WHAT IS KNOWN AND OBJECTIVE: Adherence to evidence-based drug therapy after acute myocardial infarction has increased over the last decades, but is still unsatisfactory. Our objectives are to set out to analyse patterns of evidence-based drug therapy after acute myocardial infarction (AMI), and evaluating socio-demographic differences. METHODS: A cohort of 3920 AMI patients discharged from hospital in Rome (2006-2007) was selected. Drugs claimed during the 12 months after discharge were retrieved. Drug utilization was defined as density of use (boxes claimed/individual follow-up; chronic use = 6+ boxes/365 days) and therapeutic coverage, calculated through Defined Daily Doses (chronic use: ≥80% of individual follow-up). Patterns of use of single drugs and their combination were described. The association between poly-therapy and gender, age and socio-economic position (small-area composite index based on census data) was analysed through logistic regression, accounting for potential confounders. RESULTS AND DISCUSSION: Most patients used single drugs: 90·5% platelet aggregation inhibitors (antiplatelets), 60·0%β-blockers, 78·1% agents acting on the renin-angiotensin system (ACEIs/ARBs), 77·8% HMG CoA reductase inhibitors (statins). Percentages of patients with ≥80% of therapeutic coverage were 81·9% for antiplatelets, 17·8% for β-blockers, 64·4% for ACEIs/ARBs and 76·1% for statins. The multivariate analysis showed gender and age differences in adherence to poly-therapy (females: OR = 0·84; 95% CI 0·72-0·99; 71-80 years age-group: OR = 0·82; 95% CI 0·68-0·99). No differences were observed with respect to socio-economic position. WHAT IS NEW AND CONCLUSION: The availability of information systems offers the opportunity to monitor the quality of care and identify weaknesses in public health-care systems. Our results identify specific factors contributing to non-adherence and hence define areas for more targeted health-care interventions. Our results suggest that efforts to improve adherence should focus on women and older patients.