This study aimed to better investigate the association between the red blood cell distribution width to serum albumin ratio (RA) and diabetic kidney disease (DKD) by utilizing data from the United States National Health and Nutrition Examination Survey (NHANES) and clinical data from Shanxi Provincial People’s Hospital Affiliated to Shanxi Medical University, China (SMU). A total of 3,734 and 393 participants were selected from NHANES (2011–2018) and SMU, respectively. The primary diagnosis of DKD was defined as eGFR < 60 mL/min/1.73 m2 or urinary albumin-creatinine-ratio (ACR) ≥ 30 mg/g. Multivariable logistic regression, restricted cubic spline (RCS) analysis, propensity score matching (PSM), and Kaplan-Meier survival analysis were used to evaluate the relationship between RA levels and DKD. The prevalence of DKD was estimated to be 40.38% in NHANES and 54.96% in SMU among diabetic patients. After full adjustment, higher RA levels were significantly associated with increased DKD risk in both cohorts (NHANES: OR = 1.46, 95% CI: 1.13–1.87; SMU: OR = 1.27, 95% CI: 1.01–1.60). RCS analysis revealed a nonlinear relationship between RA and all-cause mortality in DKD patients (P for nonlinearity < 0.001), with an optimal cutoff of 3.33dL/g. Patients with RA ≥ 3.33dL/g had significantly lower cumulative survival rates (log-rank P < 0.05). Subgroup analyses showed consistent associations across most strata. Higher RA level is independently associated with increased risk and poor prognosis of DKD in diabetic patients. An RA cutoff of 3.33dL/g may serve as a useful clinical marker for risk stratification.
Cheng et al. (Mon,) studied this question.