The Association between Pretreatment anemia and Overall Survival in Advanced Non-small Cell lung Cancer: A Retrospective Cohort Study Using Propensity Score Matching

Background: The purpose of this study was to investigate whether pretreatment anemia was an independent risk factor for survival in patients with advanced non-small cell lung cancer (NSCLC) after adjusting for other covariates. Methods: We used propensity score matching (PSM) to minimize the influence of confounding factors and used χ2 (categorical variables), Student's t-test (normal distribution), or Mann-Whitney U test (skewed distribution) to analyze the differences among the Hb groups. Cox regression and Kaplan-Meier analyses were used to assess the association between anemia and survival. P values < 0.05 (two-sided) were considered statistically significant. Results: The average age of the 758 selected participants was 58.2±11 years, and 210 patients (27.7%) had anemia. In the multivariate analysis, anemia was associated with a poor prognosis in the unmatched cohort (Hazards ratio (HR)=1.3, 95% (confidence interval (CI): 1.1-1.6; p= 0.008), and the matched cohort (HR=1.7, 95% CI: 1.3-2.3; p <0.001), emerging as an independent risk and prognostic factor in advanced NSCLC patients. In the Kaplan-Meier curve, the average survival time of anemic and non-anemic patients was 9.3 months (95% CI: 7.9-11.4 months) vs. 14.1 months (95% CI: 12-16.3 months) (p=0.0073) in the unmatched cohort. After propensity score matching, the average survival time of anemic and non-anemic patients was 10.9 months (95% CI: 8.8-12.9. months) vs. 17.8 months (95% CI: 16.0-23.3 months) (p <0.001). Conclusion: Pretreatment anemia was an independent risk and prognostic factor for survival in patients with advanced NSCLC. Large-scale studies are required to confirm our findings.