Red blood cell distribution width-to-albumin ratio and osteoarthritis: A cross-sectional and cohort study

BackgroundThe red cell distribution width-to-albumin ratio is a novel composite biomarker reflecting systemic inflammation and nutritional status. This study aimed to evaluate the association between the red cell distribution width-to-albumin ratio and the prevalence of osteoarthritis as well as long-term mortality risk among US adults, thereby exploring the potential value of the red cell distribution width-to-albumin ratio as a marker for osteoarthritis risk assessment and prognostic evaluation.MethodsData were obtained from the National Health and Nutrition Examination Survey in the United States, covering the years 2003-2016 and comprising 31,994 adult participants. The association between the red cell distribution width-to-albumin ratio and the prevalence of osteoarthritis was examined using logistic regression models. Additionally, prospective Cox regression models were used to evaluate the relationship between the red cell distribution width-to-albumin ratio and all-cause and cardiovascular mortality among patients with osteoarthritis. The models were adjusted for multiple important covariates, including age, sex, body mass index, race, lifestyle factors (such as smoking and alcohol consumption), and chronic comorbidities (such as diabetes, hypertension, and cardiovascular disease history). Restricted cubic spline analysis was performed to examine the nonlinear association between red cell distribution width-to-albumin ratio and mortality risk. Kaplan-Meier survival analysis, subgroup analyses, and interaction assessments were conducted to validate the robustness of the results.ResultsAmong 31,994 participants, 3150 were identified with osteoarthritis; of these, 3147 had follow-up records and were included in the survival analysis. After adjustment for key covariates, red cell distribution width-to-albumin ratio remained positively associated with the prevalence of osteoarthritis (adjusted odds ratio = 1.13, 95% confidence interval: 1.01-1.25). Compared with the lowest quartile (Q1), the highest quartile (Q4) of red cell distribution width-to-albumin ratio was significantly associated with an increased prevalence of osteoarthritis (odds ratio = 1.27, 95% confidence interval: 1.09-1.48). During a median follow-up of 92 months, higher red cell distribution width-to-albumin ratio significantly predicted all-cause mortality (hazard ratio = 2.11, 95% confidence interval: 1.74-2.56) and cardiovascular mortality (hazard ratio = 2.08, 95% confidence interval: 1.68-2.58) among patients with osteoarthritis. Further analysis revealed a significant nonlinear J-shaped association between red cell distribution width-to-albumin ratio and all-cause mortality risk among patients with osteoarthritis, with a threshold value of 2.84, above which mortality risk increased markedly (p < 0.05).ConclusionsThis study suggests that the red cell distribution width-to-albumin ratio is associated with osteoarthritis prevalence and mortality risk among adults with osteoarthritis. Red cell distribution width-to-albumin ratio may represent a potential risk marker for osteoarthritis-related risk assessment and prognostic evaluation.