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% beta-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 beta-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.