# Incidence of and Risk Factors for Anti-PD-1/PD-L1- Associated Diarrhea and Colitis: A Retrospective Cohort Study of the Chinese Population

## TL;DR

This study finds that 4.6% of Chinese patients on anti-PD-1/PD-L1 therapy experience diarrhea or colitis, with digestive tumors increasing risk and platinum drugs lowering it.

## Contribution

The study identifies specific risk and protective factors for immune-related diarrhea/colitis in a Chinese cohort receiving anti-PD-1/PD-L1 therapy.

## Key findings

- IMDC incidence was 4.6%, with colitis at 0.67% in 1186 Chinese patients.
- Digestive system tumors increased IMDC risk (OR 2.79), while platinum agents reduced it (OR 0.41).
- Colitis was the third most common immune-related adverse event, causing ICI discontinuation in 15.6% of cases.

## Abstract

Background and Objectives: The prevalence of and risk factors for immune checkpoint inhibitor-associated diarrhea and colitis (IMDC) in the Chinese population are unclear. This study aimed to estimate IMDC incidence and identify potential risk factors. Materials and Methods: We reviewed the electronic medical records from Beijing Friendship Hospital (2015–2022) to identify the patients treated with immune checkpoint inhibitors. The primary outcome was IMDC occurrence. The demographics, cancer type, baseline labs, and concurrent medications were analyzed. The univariable and multivariable analyses validated the associated factors. Results: Among 1186 patients (median follow-up: 217 days), the IMDC incidence was 4.6%, with colitis at 0.67%. Digestive system tumors increased the IMDC risk (OR 2.79, 95% CI 1.42–5.75, p = 0.004), while platinum agents decreased it (OR 0.41, 95% CI 0.21–0.78, p = 0.008). PPIs, antibiotics, NSAIDs, and glucocorticoids showed no significant association. Colitis was the third most common irAE, leading to ICI discontinuation (15.6%). Conclusions: IMDC prevalence is 4.6% in the Chinese population, the third most frequent irAE causing ICI discontinuation. Digestive tumors and platinum agents are risk and protective factors, respectively, while other medications show no significant impact.