Preoperative Advanced Lung Cancer Inflammation Index and Acute Kidney Injury After Adult Cardiac Surgery: A Retrospective Cohort Study

Acute kidney injury (AKI) is common after cardiac surgery. We assessed the association between the preoperative advanced lung cancer inflammation index (ALI) and postoperative AKI. This retrospective cohort included adults undergoing cardiac surgery from 2 January 2019 to 16 March 2026. The primary outcome was the first in-hospital AKI recorded within 168 h using stored Kidney Disease: Improving Global Outcomes creatinine and kidney-replacement-therapy classifications. Among 11,890 adults, AKI was recorded in 3380 (28.4%). Each ALI doubling was associated with a lower adjusted AKI rate (hazard ratio, 0.83; 95% confidence interval, 0.80–0.86; p < 0.001); the fixed-horizon risk ratio was 0.86 (95% confidence interval, 0.83–0.88; p < 0.001). Adjustment for available preoperative shock, resuscitation, intubation, infective endocarditis, acute aortic disease, and catecholamine indicators attenuated the hazard ratio to 0.90 (95% confidence interval, 0.87–0.94). Association magnitude differed across mutually exclusive procedure categories (interaction p < 0.001). The coefficient constraints imposed by ALI were rejected, and the positive BMI association persisted with flexible modeling. Lower ALI was associated with more recorded AKI, but differential monitoring, residual confounding, and unsupported component constraints limit interpretation of the composite.