The inflammatory burden index is a superior systemic inflammation biomarker for the prognosis of non-small cell lung cancer.

Background: Systemic inflammation, the most representative tumour-host interaction, plays a crucial role in disease progression and prognosis in patients with non-small cell lung cancer (NSCLC). Few studies have compared the performance of existing haematological systemic inflammation biomarkers in predicting the prognosis of NSCLC patients. The purpose of this study was to compare the prognostic value of existing systemic inflammation biomarkers and determine the optimal systemic inflammation biomarker in patients with NSCLC through a multicentre prospective study.

Methods: The predictive accuracy of systemic inflammation biomarkers for prognostic assessment in NSCLC was assessed using C-statistics. Inter-group differences in survival were assessed using the log-rank test and visualized using the Kaplan-Meier method. A restricted cubic spline (RCS) curve was used to explore the association between the biomarkers and survival. Independent prognostic biomarkers for overall survival were determined using multivariable Cox proportional hazards regression analysis. Logistic regression analysis was used to determine independent predictors of 90-day outcomes, length of hospitalization, hospitalization expenses and cachexia.

Results: The inflammatory burden index (IBI) had the highest C-statistic for predicting the prognosis of patients with NSCLC, reaching 0.640 (0.617, 0.663). Patients with a high IBI had significantly worse outcomes than those with a low IBI (35.46% vs. 57.22%; log-rank P < 0.001). The IBI was also able to differentiate the prognosis of patients with NSCLC with the same pathological stage. The RCS curve showed an inverted L-shaped dose-response relationship between the IBI and survival of patients with NSCLC. Multivariable Cox proportional hazards regression analysis showed that a high IBI was an independent risk factor for death of patients with NSCLC (hazard ratio = 1.229, 95% confidence interval [CI]: 1.131-1.335, P < 0.001). A high IBI was an independent predictor of 90-day outcomes (odds ratio [OR] = 1.789, 95% CI: 1.489-2.151, P < 0.001), prolonged hospital stays (OR = 1.560, 95% CI: 1.256-1.938, P < 0.001), high hospitalization expenses (OR = 1.476, 95% CI: 1.195-1.822, P < 0.001) and cachexia (OR = 1.741, 95%CI = 1.374-2.207, P < 0.001) in patients with NSCLC.

Conclusions: The IBI was independently associated with overall survival, 90-day outcomes, length of hospitalization, hospitalization expenses and cachexia in NSCLC patients. As an optimal systemic inflammation biomarker, the IBI has broad clinical application prospects in predicting the prognosis of patients with NSCLC.