The predictive value of systemic inflammation response index and albumin-to-globulin ratio for prognosis in non-small cell lung cancer

We investigated whether inflammatory markers would be significant prognostic factors for survival in patients with non-small-cell lung cancer (NSCLC). This was a retrospective cohort study including 748 consecutive Chinese NSCLC patients. The relationships of inflammatory markers with clinicopathologic characteristics and prognosis were analyzed by chi-squared test and Cox regression. Restricted cubic splines (RCS) with 4 knots were used to flexibly model non-linear relationships between markers and overall survival (OS). Survival was estimated using Kaplan-Meier curves. In multivariate analysis, the systemic inflammation response index (SIRI) and albumin-to-globulin ratio (AGR) were independently associated with OS (HR: 1.506, 95% CI: 1.224-1.852; HR: 0.749, 95% CI: 0.608-0.923). RCS showed a non-linear association for SIRI (P for non-linear = 0.004) and a linear association for AGR (P for non-linear = 0.258). We constructed a 3-tier SIRI-AGR score: Score 1 (low risk: SIRI ≤ 0.91 and AGR > 1.19), Score 2 (intermediate: either SIRI > 0.91 or AGR ≤ 1.19, but not both), Score 3 (high risk: SIRI > 0.91 and AGR ≤ 1.19). Patients with Score 3 had significantly shorter OS (HR: 1.974; 95% CI: 1.486-2.622). Time-dependent ROC showed stable predictive performance with AUC ≈ 0.70 throughout follow-up. The SIRI-AGR score is an independent, convenient, and low-cost prognostic factor for NSCLC. It can serve as a useful indicator for risk stratification and clinical decision-making.