Red cell distribution width/albumin ratio and mortality risk in rheumatoid arthritis patients: Insights from a NHANES study

Background: Despite the established negative regulatory effects observed in various diseases like cardiovascular disease and diabetes, the distinct impact of red cell distribution width (RDW) to albumin ratio (RAR) on mortality within the realm of rheumatoid arthritis (RA) remains obscure. This study sought to explore the relationship between RAR and mortality in RA patients. Methods: A cohort of 2151 adults with RA from the National Health and Nutrition Examination Survey (NHANES) spanning 2003-2016 was analyzed for RAR levels derived from red cell distribution width and albumin concentrations. Utilizing Cox regression analysis, Kaplan-Meier curves, and Restricted Cubic Spline (RCS) models, we assessed the association between RAR levels and RA mortality while adjusting for potential confounding variables. Results: Participants with higher RAR had a twofold to threefold increased risk of all- cause (HR = 3.10, 95% CI: 2.26-4.24) and cardiovascular mortality (HR = 2.46, 95%CI: 1.26-4.79) versus lower RAR. Kaplan-Meier analysis revealed that the higher RAR group had a significantly lower survival rate compared to the lower RAR group for both all- cause and cardiovascular mortality (both p < .0001), with a more pronounced effect observed for all- cause mortality. Furthermore, the RCS- fitted Cox regression model illustrated a nonlinear positive correlation between RAR levels and RA mortality. Conclusion: Overall, a higher RAR was associated with an increased risk mortality in RA patients. These findings underscore the potential of RAR as a prognostic biomarker in predicting outcomes in RA.