Elevated red cell distribution width-to-albumin ratio is associated with prevalent lung cancer in the U.S. population

Red blood cell distribution width-to-albumin ratio (RAR) has recently been suggested as a potential inflammatory biomarker in various malignancies. However, its role in lung cancer (LC) remains underexplored. Data utilized in this study were extracted from the National Health and Nutrition Examination Survey spanning 2003 to 2020. Associations between RAR and LC were explored using logistic regression and multivariable adjustment techniques. To investigate potential nonlinear trends, restricted cubic spline modeling was applied. The diagnostic capacity of RAR was further assessed through analysis of receiver operating characteristic curves. Subgroup analysis by race and sex was conducted to assess heterogeneity. All analyses were weighted to account for the sampling design. Through screening, a total of >42,746 respondents were included in our study, among whom 89 cases of LC were identified. After applying sample weighting, a notable link was identified between the RAR and higher odds of prevalent LC. Logistic regression analysis showed that, compared with the RAR < 0.287, the 0.287 to 0.310 category was associated with lower odds of prevalent LC, whereas the >0.341 category was associated with higher odds; the 0.310 to 0.341 category was not significantly associated with LC prevalence. Additionally, increased red blood cell distribution width (RDW) and reduced serum albumin (Alb) concentrations were independently associated with higher odds of LC prevalence. Restricted cubic spline analysis indicated a nonlinear relationship between Alb and LC, while both RDW and RAR showed linear associations. Subgroup analysis revealed that RAR had a consistent harmful trend among people of different genders, educational levels, and alcohol consumption levels. Receiver operating characteristic analysis confirmed that RAR, RDW, and Alb had modest discriminative ability for identifying prevalent LC cases in this cross-sectional population. RAR is significantly associated with LC prevalence in a nationally representative sample, suggesting a notable epidemiologic association that warrants further longitudinal investigation.