Endothelial injury biomarker EASIX predicts mortality risk in adults with chronic obstructive pulmonary disease: A...

Endothelial dysfunction has been implicated in the pathogenesis and progression of chronic obstructive pulmonary disease (COPD). This study aimed to examine the utility of the Endothelial Activation and Stress Index (EASIX), a novel biomarker of endothelial injury, for predicting mortality risk in US adults with COPD. Data from 1957 COPD participants in the 1999-2018 National Health and Nutrition Examination Survey were analyzed. EASIX was calculated from lactate dehydrogenase, serum creatinine, and platelet count. Multivariable Cox proportional hazard regression models were used to assess associations between log2-transformed EASIX tertiles (T1 lowest and T3 highest) and all-cause, cardiovascular disease (CVD), and chronic lower respiratory disease (CLRD) mortality by reporting hazard ratios and 95% confidence intervals. Over a median follow-up period of 79 months, 672 (27.70%) participants died, including 150 (22.32%) from CVD and 186 (27.68%) from CLRD. Compared to the T1 group, the hazard ratio (95% confidence intervals) for the T2 and T3 groups were 1.14 (0.85-1.53) and 2.42 (1.85-3.17), respectively, for all-cause mortality, 1.46 (0.90-2.38) and 3.02 (1.76-5.18), respectively, for CVD mortality, and 1.65 (1.00-2.71) and 2.56 (1.58-4.14), respectively, for CLRD mortality. Restricted cubic spline curves demonstrated a positive nonlinear relationship between log2-transformed EASIX and mortality risk. Subgroup analysis indicated the associations between log2-transformed EASIX and all-cause and CLRD mortality were more pronounced in patients with a history of CVD. EASIX independently predicts all-cause, CVD, and CLRD mortality in US individuals with COPD, supporting its potential utility for risk stratification and personalized management.