Use of proton pump inhibitors and mortality among Icelandic prostate cancer patients

Proton pump inhibitors (PPIs) are commonly used drugs among cancer patients. Due to conflicting reports on their safety, we aimed to determine whether PPI use is associated with mortality among prostate cancer patients. In this population-based cohort study, we identified incident diagnoses of prostate cancer between 2007 and 2012 (n = 1058). Follow-up was from 12 months after diagnosis until death, emigration or end the of study. Post-diagnosis use was defined as >= 2 filled prescriptions following diagnosis. We used time-dependent Cox proportional hazard regression models to compute hazard ratios (HRs) and 95% confidence intervals (CIs) for prostate cancer-specific and all-cause mortality associated with post-diagnosis use of PPIs. We identified 347 (32.8%) post-diagnosis PPI users and 711 (67.2%) non-users after diagnosis. Of the 347 patients using PPIs after diagnosis, 59 (17.0%) died due to any cause and 22 (6.3%) due to prostate cancer, compared with 144 (20.3%) and 76 (10.7%) among non-users after diagnosis, respectively. Post-diagnosis PPI use was not associated with prostate cancer-specific mortality (HR 0.88; 95% CI: 0.52-1.48) or all-cause mortality (HR 1.02; 95% CI: 0.73-1.43). Contrary to a previous report, this study did not find evidence of an association between post-diagnosis PPI use and mortality among prostate cancer patients.