Background:Gastrointestinal immune-related adverse events (GI-irAEs) are recognized complications of immune checkpoint inhibitors (ICIs), but their prognostic relevance and associated risk factors remain unclear. This study aimed to assess whether baseline nutritional status, measured using the prognostic nutritional index (PNI), modifies the prognostic impact of GI-irAEs, and to identify clinical factors associated with their occurrence.Methods:We retrospectively analyzed 1104 cancer patients treated with ICIs at a single institution. GI-irAEs were defined as gastrointestinal symptoms requiring clinical intervention. Patients were stratified by irAE type and PNI (≥40 vs. <40), and differences in survival and treatment response were evaluated. Potential risk factors for developing GI-irAEs were also examined.Results:GI-irAEs occurred in 2.7% of patients and were associated with prolonged overall survival (median: 28.7 vs. 14.0 months) among those with PNI ≥ 40. This survival advantage was not observed in patients with PNI < 40. The PNI-dependent prognostic pattern was specific to GI-irAEs and not observed for non-GI irAEs. Similar trends were confirmed in 4- and 8-week landmark analyses. Differences in objective response rate and disease control rate by PNI status were most pronounced in patients with GI-irAEs. The use of anti-CTLA-4 antibodies was significantly associated with GI-irAE development (odds ratio 4.24; 95% confidence interval 1.73–10.39).Conclusions:GI-irAEs appear to confer a survival benefit primarily in patients with preserved nutritional status. PNI may serve as a useful tool to contextualize the clinical relevance of GI-irAEs and help identify patients most likely to benefit from immune activation during ICI therapy.
背景：胃肠道免疫相关不良事件（GI-irAEs）是免疫检查点抑制剂（ICIs）治疗中已知的并发症，但其预后意义及相关风险因素尚不明确。本研究旨在评估基线营养状态（通过预后营养指数PNI测量）是否会改变GI-irAEs的预后影响，并识别与其发生相关的临床因素。 方法：我们回顾性分析了单中心接受ICIs治疗的1104例癌症患者。GI-irAEs定义为需要临床干预的胃肠道症状。根据irAE类型和PNI（≥40 vs. <40）对患者进行分层，评估生存期和治疗反应的差异，同时探讨发生GI-irAEs的潜在风险因素。 结果：2.7%的患者发生GI-irAEs，在PNI ≥ 40的患者中，GI-irAEs与总生存期延长相关（中位生存期：28.7个月 vs. 14.0个月）。该生存优势在PNI < 40的患者中未观察到。这种PNI依赖的预后模式为GI-irAEs所特有，在非GI-irAEs中未出现。4周和8周界标分析也证实了相似趋势。在发生GI-irAEs的患者中，客观缓解率和疾病控制率因PNI状态产生的差异最为显著。抗CTLA-4抗体的使用与GI-irAE发生显著相关（比值比4.24；95%置信区间1.73–10.39）。 结论：GI-irAEs带来的生存获益主要见于营养状态良好的患者。PNI可作为评估GI-irAEs临床相关性的有效工具，有助于识别最可能从ICI治疗期间的免疫激活中获益的患者群体。
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