Objective: Adherence to evidence-based drug therapy after acute myocardial infarction has increased over the last decades, but is still unsatisfactory. The objectives are of this study were to analyse patterns of evidence-based drug therapy after acute myocardial infarction (AMI), and evaluate socio-demographic differences.
Methods: A cohort of 3920 AMI patients discharged from hospital in Rome (2006-07) was selected. Drugs claimed during the 12 months after discharge were retrieved. Drug utilisation 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% or more of individual follow-up). Patterns of use of single drugs and their combinations were described. The association between polytherapy and gender, age and socio-economic status (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% or higher 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 polytherapy (females: OR = 0.84; 95% CI, 0.72 to 0.99; 71-80 years age-group: OR = 0.82; 95% CI, 0.68 to 0.99). No differences were observed with respect to socio-economic position.
Conclusions: The availability of information systems offers the opportunity to monitor the quality of care and identify weaknesses in public health-care systems. These results identify specific factors contributing to non-adherence and hence define areas for more targeted health-care interventions. The results suggest that efforts to improve adherence should focus on women and older patients.