Adherence to prescribed drugs among 65-74 years old men diagnosed with abdominal aortic aneurysm or peripheral arterial disease in a randomized screening trial

Purpose: Antiplatelet and statin treatment reduce progression of CVD. We aimed to examine adherence to antiplatelet and statin therapy for participants in a vascular screening trial diagnosed with AAA or PAD. Methods: Data from the VIVA screenings cohort for vascular disease were combined with data from Danish registers from 2007 to 2016. Initiation of antiplatelet and statin treatment was measured within 90 days for non-users at baseline. Persistence was measured by time to first break of >100 days. Proportion of days covered ≥80% was used as categorical cut-off for adherence during 5 years of follow-up. Result: Among 18,748 screened participants, we identified 619 with AAA and 2,052 with PAD. Among non-users at baseline 64% and 61% initiated antiplatelet and statin within 90 days, 49% and 45% were persistence and 43% and 38% were adherent. Only drug user status at baseline provided important information on antiplatelet and statin adherence. Conclusion: The 5-year adherence to antiplatelet and statin treatment was suboptimal for participants in a screening program for vascular disease. For non-users at screening adherence was low. Research initiatives are required to increase adherence among non-users at screening to improve screening efficacy and cost effectiveness in future trials.