Abstract
This study examined the relationship between the neutrophil-to-albumin ratio (NPAR) and both all-cause and cardiovascular mortality in U.S. patients with cardiovascular disease (CVD) and abnormal glucose metabolism, using NHANES data from 1999 to 2018. Restricted cubic spline analysis identified a significant nonlinear association between NPAR and mortality (p < 0.001). Cox regression results showed that patients in the highest NPAR group (T3, ≥ 15.8) had higher risks of all-cause (HR 1.75, 95% CI 1.50-2.04) and cardiovascular mortality (HR 2.03, 95% CI 1.53-2.68) compared to the lowest group (T1, < 13.5), both with p < 0.0001. Kaplan-Meier survival curves confirmed greater mortality in the T3 group. Mediation analysis found that renal function, measured by eGFR, accounted for 14.49% of the effect on all-cause mortality and 13.38% on cardiovascular mortality. Among the 3163 participants, 1342 experienced all-cause deaths and 462 cardiovascular deaths. This study demonstrated a significant correlation of high NPAR and increased mortality in patients with abnormal glucose metabolism and CVD, suggesting that NPAR may represent a reliable predictor of mortality risk in this population, and emphasizing the importance of both inflammation and renal function monitoring.