Aspirin overuse in primary prevention: nationwide temporal trends in low-dose aspirin therapy for primary prevention of cardiovascular disease in adults with and without diabetes

Abstract Background Aspirin therapy for primary prevention of cardiovascular disease (CVD) is controversial. European Society of Cardiology guideline recommendations have changed in the last decades, and aspirin is currently not recommended in individuals with low/moderate cardiovascular (CV) risk but may be considered in high-risk individuals with diabetes. Purpose We report temporal trends in primary prevention aspirin prescription among individuals with and without diabetes and describe characteristics of incident aspirin users. Methods Using Danish nationwide registries, we identified incident and prevalent aspirin users in a population ≥40 years without CVD, eligible for primary preventive aspirin therapy from 2000 through 2020. Temporal trends in aspirin use with and without diabetes were assessed, as were CV risk factors among incident users. Individuals in Denmark are primarily seen by general practitioners who have a gate-keeper function for secondary hospital-based care. Results A total of 522,680 individuals started aspirin therapy during the study period. The number of incident users peaked in 2002 (39,803 individuals, 1.78% of the eligible population) and was lowest in 2019 (11,898 individuals, 0.49%), with similar trends for subjects with and without diabetes (Figure 1). A large proportion of incident users had no CV risk factors (diabetes, hypertension, hypercholesterolemia, or chronic obstructive pulmonary disease [a proxy for smoking]); however, this proportion decreased from 53.9% in 2000 to 30.9% in 2020 (Figure 2). The number of prevalent aspirin users peaked at 7.7% in 2008 and was 3.3% in 2020. For subjects with diabetes, the peak was observed in 2009 at 38.5% and decreased to 17.1% in 2020. Conclusion Prescription of aspirin for primary prevention of CVD has decreased over the last two decades in individuals both with and without diabetes. However, aspirin appears to be inappropriately prescribed in many primary prevention adults as a large proportion of incident users had no CV risk factors. Efforts to inform appropriate prescription of aspirin are needed, e.g., by improved guidance for general practitioners.Figure 1Figure 2