Association of Proton Pump Inhibitor Use and Immune Checkpoint Inhibitor-Mediated Acute Kidney Injury: A Meta-Analysis and a Review of Related Outcomes

<b><i>Introduction:</i></b> Immune checkpoint inhibitors (ICIs) have revolutionized cancer treatment. However, they pose the risk of immune-related adverse events, including ICI-mediated acute kidney injury (ICI-AKI). Recent studies have implicated proton pump inhibitors (PPIs) as potential contributors to ICI-AKI development. This meta-analysis examines the association between PPI use and ICI-AKI, exploring a potential modifiable risk factor in ICI therapy while also reviewing the possible outcomes of ICI-AKI. <b><i>Methods:</i></b> We conducted a comprehensive systematic review and meta-analysis of observational studies, assessing the risk of ICI-AKI in cancer patients concurrently using PPIs and potential outcomes. Odds ratios (ORs) were pooled using random-effects models. Subgroup analyses and sensitivity analyses were performed to evaluate heterogeneity and potential biases. <b><i>Results:</i></b> A total of 14 studies involving 12,694 patients were included. In total, we analyzed 639 patients with all-cause AKI and 779 patients with ICI-AKI. The pooled OR for the overall incidence of AKI from all-causes was 1.57 (95% confidence interval [CI] 1.02–2.40) among patients on PPIs. Specifically, the risk of ICI-AKI associated with PPI use was significantly higher, with a pooled OR of 1.84 (95% CI 1.16–2.90). This indicates approximately 84% higher likelihood of developing ICI-AKI with concurrent use of PPIs. Additionally, among patients with ICI-AKI, 67% had complete or partial recovery of renal function, 32% progressed to chronic kidney disease (CKD), and about 36% died during a follow-up period of at least 3 months. <b><i>Conclusion:</i></b> This meta-analysis highlights the importance of cautious PPI prescription in cancer patients undergoing ICI therapy. Clinicians are advised to evaluate the risks and benefits of PPI use and consider alternative therapies when feasible.