The association between adult red blood cell width to albumin ratio (RAR) and psoriasis: a retrospective cross-sectional study

Abstract

This study aims to investigate the association between the red blood cell distribution width-to-albumin ratio (RAR), a biomarker reflecting systemic inflammation and nutritional status, and psoriasis prevalence in a nationally representative U.S. population. Cross-sectional data from 11,668 adults in the National Health and Nutrition Examination Survey (NHANES) (2003–2006 and 2009–2014) were analyzed. Psoriasis was defined by self-reported clinician diagnosis. RAR was calculated as red cell distribution width (RDW) (%) divided by serum albumin (g/dL). Multivariable logistic regression models were used, and Restricted Cubic Spline (RCS) analysis was performed to assess the potential linear relationship. Additionally, subgroup and sensitivity analyses were conducted to evaluate the robustness of the findings. Of the 11,668 adults included in the study, 280 were diagnosed with psoriasis. Elevated Ln-transformed RAR (ln-RAR) was independently associated with higher psoriasis prevalence (fully adjusted Odds ratios, OR = 3.57, 95% CI: 1.37–8.92, P = 0.003). A linear dose-response relationship was confirmed (P for non-linearity > 0.05) in RCS. In the subgroup analysis, effect size of RAR on the presence of psoriasis in subgroups was stable (all P values > 0.05). The sensitivity analysis was consistent with the main results, further supporting the stability of our conclusion. RAR is a potential biomarker that shows positive correlation with the prevalence of psoriasis, with a linear association. Further prospective studies are needed to confirm these findings.