Predictors of statin adherence in primary care using real-world data

Abstract Purpose The objective of this study was to identify predictors of statin adherence in the primary and secondary prevention of CVD among patients in the first two years after the date of first prescription using real-world data. Methods The Electronic Practice Based Research Network Linked Dataset was used in this study. Statin adherence was calculated using a modified proportion of days covered (PDC) formula. Individuals with PDC ≥ 80% during the two years of observation period were considered as adherent. All analyses were performed with R software. Descriptive and multivariate logistic regression analyses were performed. Sensitivity analysis was performed using the Akaike Information Criterion model selection method. Results Overall, 3,432 patients accounting for 57,227 visits met the selection criteria. The mean PDC was 91.6% (±22.2%), and 72.0% of the patients were adherent to statins (PDC ≥ 80%) in the first two years after the date of first prescription. After adjusting for all other variables, statin adherence was positively associated with age (AOR 1.7, 95% CI 1.4 – 2.0), SEIFA index (AOR 1.8, 95% CI 1.2 – 2.6), polypharmacy (AOR 1.8, 95% CI 1.3 – 2.5) and comorbidities (AOR 1.4, 95% CI 1.1 – 1.7), and negatively associated with the number of statin types (AOR 0.6, 95% CI 0.5 – 0.9) and smoking status (AOR 0.7, 95% CI 0.6 – 0.9). The sensitivity analysis showed similar results as the regression model. Conclusions Statin adherence is influenced by an aging, multimorbid population, who are exposed to polypharmacy, multiple statin options and socioeconomic diversity. Key points Adherence in the first two years after the first date of statin prescription was measured as proportion of days covered (PDC) The mean PDC was 91.6% (±22.2%) 72.0% of the patients were adherent to statins, with PDC ≥ 80% Statin adherence was positively associated with age, area-based social advantage and disadvantage index, polypharmacy and comorbidities Statin adherence was negatively associated with the number of statin types prescribed to the patients and the smoking status of patients Plain Language Summary The objective of this study was to identify predictors of statin adherence among patients in the first two years after the date of first prescription using real-world data. The dataset used was the Electronic Practice Based Research Network Linked Dataset. Statin adherence was calculated using proportion of days covered (PDC). A PDC ≥ 80% during the two years of observation period were considered as adherent. Overall, 3,432 patients were eligible for this study, and 72.0% of them were adherent to statins in the first two years after the date of first prescription. Statin adherence was positively associated with age, area-based social advantage and disadvantage index, number of medicines taken by the patient and number of chronic conditions that the patient suffered. Moreover, statin adherence was negatively associated with the number of statin types prescribed to the patients and smoking status of patients.