Self-controlled Case Series Study for Acute Kidney Injury after Starting Proton Pump Inhibitors or...

Area of Science:

• Nephrology
• Oncology
• Pharmacology

Background:

• Proton pump inhibitors (PPIs) and potassium-competitive acid blockers (PCABs) are commonly prescribed for acid-related disorders.
• Patients with cancer often require these medications alongside anti-cancer therapies.
• The potential risk of acute kidney injury (AKI) associated with these drug classes in cancer patients is not fully understood.

Purpose of the Study:

• To investigate the association between the initiation of PPIs or PCABs and the risk of AKI in patients with cancer.
• To examine potential sex-specific differences in AKI risk.
• To assess the influence of concomitant anti-cancer drug use on AKI risk.

Main Methods:

• A self-controlled case-series study design was employed using claims data from 12,422 cancer patients in Japan (2017-2019).
• Defined control (days -120 to -1) and risk periods (days 0 to +30, days +31 to +365) relative to drug initiation.
• Calculated incidence rate ratios (IRRs) and 95% confidence intervals (CIs), adjusting for anti-cancer drugs and analyzing sex differences.

Main Results:

• An increased risk of AKI was observed during the initial 30 days (Risk Period 1: IRR 2.05, 95% CI 1.12-3.72).
• A slight reduction in AKI risk was noted beyond 30 days (Risk Period 2: IRR 0.60, 95% CI 0.36-1.00).
• Males showed a significant increase in AKI risk within 30 days (IRR 2.18, 95% CI 1.10-4.32) and a reduced risk thereafter (IRR 0.48, 95% CI 0.26-0.89).

Conclusions:

• Initiation of PPIs or PCABs is associated with an elevated risk of AKI in cancer patients, particularly within the first 30 days.
• Male cancer patients appear to be at a higher risk of AKI during the early phase of PPI/PCAB use.
• Vigilant monitoring for AKI is recommended for cancer patients commencing PPI or PCAB therapy, with attention to sex-specific risks.