Association Between Endothelial Activation and Stress Index and Microalbuminuria

The aim of this study was to investigate the association between endothelial activation and stress index (EASIX), a composite marker of endothelial dysfunction, and microalbuminuria.

This cross-sectional study included adult patients from Departments of General Practice and Geriatrics at the First Affiliated Hospital of Fujian Medical University between January 2017 and December 2023. Microalbuminuria was defined as a urinary albumin-to-creatinine ratio (UACR) of 30-300 mg/g. EASIX was calculated as lactate dehydrogenase (U/L) × serum creatinine (mg/dL) / platelet count (10⁹/L). The association of EASIX with microalbuminuria was evaluated using logistic regression models, restricted cubic splines (RCS), and subgroup analyses.

Among 3,126 patients, 403 (12.9%) had microalbuminuria and exhibited significantly higher EASIX levels compared with those with normal UACR [median (P25~P75): 0.63 (0.47-0.90) vs 0.62 (0.48-0.82) mg/g, P = 0.019]. Multivariate linear regression identified EASIX as an independent factor for lnUACR (β = 0.100, 95% CI: 0.115~0.233, P<0.001). Logistic regression further showed that EASIX was independently associated with microalbuminuria (OR = 1.420, 95% CI:1.167~1.728, P < 0.001). In the fully adjusted model, EASIX quartiles remained independently associated with microalbuminuria (OR = 1.395, 95% CI: 1.147~1.698, P < 0.001). RCS analysis revealed a U-shaped non-linear association (P for non-linear = 0.007), with an inflection point at EASIX = 0.625, above which the risk of microalbuminuria increased significantly. This association remained consistent across subgroups stratified by age, sex, body mass index (BMI), and hypertension or diabetes status in patients with EASIX > 0.625, with no significant interactions.

This study provides evidence that EASIX, a composite marker derived from routine blood tests, is independently associated with microalbuminuria. A threshold of 0.625 for the EASIX may warrant further investigation in longitudinal studies.