Context: Proton pump inhibitors (PPIs) are widely used drugs for gastric acid-related diseases and may affect the gut microbiome.

Objective: We aimed to evaluate the associations of PPI use with risks of cardiovascular disease (CVD) and all-cause mortality in patients with type 2 diabetes (T2D).

Methods: We analyzed the associations of PPI use with risks of coronary artery disease (CAD), myocardial infarction (MI), heart failure (HF), stroke, and all-cause mortality in 19 229 adults with T2D using data from the UK Biobank study.

Results: During a median follow-up of 10.9 to 11.2 years, we documented 2971 CAD, 1827 MI, 1192 HF, and 738 stroke cases, along with 2297 total deaths. PPI use was significantly associated with higher risks of CAD (hazard ratio [HR], 1.27; 95% CI, 1.15-1.40), MI (HR, 1.34; 95% CI, 1.18-1.52), HF (HR, 1.35; 95% CI, 1.16-1.57), and all-cause mortality (HR, 1.30; 95% CI, 1.16-1.45). No statistically significant association was observed between PPI use and stroke (HR, 1.11; 95% CI, 0.90-1.36). The results were consistent in the subgroup analyses stratified by factors including indications of PPI, antidiabetic medication use, and antiplatelet drug use. Analyses in a 1:1 propensity score-matched cohort of PPI users vs nonusers yielded similar results.

Conclusion: Our data suggest that PPI use is associated with higher risks of CVD events and mortality among patients with T2D. The benefits and risks of PPI use should be carefully balanced among patients with T2D, and monitoring of adverse CVD events during PPI therapy should be enhanced.