Incidence and risk factors of infections in lung cancer patients receiving immunotherapy combined with chemotherapy: a real-world retrospective study.

This single-center, real-world retrospective cohort study assessed the incidence, risk factors, and clinical risk stratification of infections in lung cancer (LC) patients receiving immune checkpoint inhibitors (ICIs) combined with chemotherapy. This study comprised a cohort of 616 consecutive LC patients who received ICI-based chemotherapy during hospitalization between January 2020 and December 2025. LASSO regression followed by multivariable logistic regression was used to identify independent risk factors. Optimal cutoffs for score construction were determined using receiver operating characteristic (ROC) curve analysis combined with the Youden index, and internal validation was performed with 1,000 bootstrap resamples. The overall infection rate was 9.09% (56/616), with pulmonary infection being the most common site (64.29%), and gram-negative bacteria being most predominant (50.00%) Among culture-positive specimens, CRKP, MRSA, and CRPA accounted for 40.00%, 33.33%, and 25.00% of their respective species. Multivariable analyses identified ECOG performance status ≥2 (OR=3.993, 95% CI: 1.520-10.926, P=0.005), C-reactive protein (CRP) (OR=1.114, 95% CI: 1.079-1.159, P<0.05) as independent risk factors. In summary, infections appear to be a major complication in LC patients receiving ICIs combined with chemotherapy, often involving drug-resistant pathogens. A scoring system based on seven routinely available clinical parameters demonstrated good discrimination and internal stability in bootstrap validation, potentially aiding in the identification of high-risk patients for preventive measures.