Use of Proton Pump Inhibitors and the Risk of Acute Kidney Injury Among Patients with Rheumatoid Arthritis: Cohort Study.

INTRODUCTION: Recent observational studies have indicated that use of proton pump inhibitors may be associated with adverse renal outcomes. The objective of this study was to investigate whether the use of proton pump inhibitors increases the risk of acute kidney injury among patients with rheumatoid arthritis.

METHODS: We conducted the study as a historical prospective cohort study, including patients with rheumatoid arthritis, 30-84 years of age, during 2004-2015. Among these, we identified and matched episodes of use and non-use of proton pump inhibitors (control episodes) 1:4 on the propensity score, including 24,579 episodes of use of proton pump inhibitors and 98,230 control episodes. The primary outcome was a first diagnosis of acute kidney injury and the secondary outcome was any serious renal event (acute kidney injury or chronic kidney disease). The primary time point for analysis was 120 days after study entry.

RESULTS: The incidence rate of acute kidney injury was 2.2 per 1000 person-years during episodes of use of proton pump inhibitors and 0.9 during control episodes. Use of proton pump inhibitors was associated with a significantly increased risk of acute kidney injury (hazard ratio 2.30, 95% confidence interval 1.26-4.20). The absolute risk difference was 40 (95% confidence interval 8-99) events of acute kidney injury per 100,000 episodes of use of proton pump inhibitors. Use of proton pump inhibitors was also associated with a significantly increased risk of the secondary outcome of any serious renal event (hazard ratio 2.61, 95% confidence interval 1.80-3.80).

CONCLUSIONS: This cohort study among patients with rheumatoid arthritis found a significantly increased risk of acute kidney injury associated with the use of proton pump inhibitors. These findings may help inform clinical decision making when considering the risks and benefits of proton pump inhibitor treatment in rheumatoid arthritis.