Neutrophil percentage-to-albumin ratio is associated with in-hospital mortality in patients with acute aortic dissection: a multicenter retrospective cohort study

Early risk stratification remains challenging in patients with acute aortic dissection (AAD). This study aims to evaluate the prognostic value of neutrophil percentage-to-albumin ratio (NPAR) for in-hospital mortality in patients with acute aortic dissection. We performed a multicenter retrospective cohort study including 2,596 patients with AAD from five tertiary hospitals in China between 2010 and 2021. NPAR was calculated as neutrophil percentage divided by serum albumin concentration at admission. Patients were categorized into tertiles according to NPAR levels. The primary outcome was all-cause in-hospital mortality. Cox proportional hazards models were applied to assess the association between NPAR and mortality, adjusting for demographic and clinical confounders. Discriminative performance was evaluated using receiver operating characteristic (ROC) analysis. A total of 576 patients (22.2%) died during hospitalization. Higher NPAR levels were independently associated with an increased risk of in-hospital mortality (adjusted hazard ratio per 10-unit increase = 1.71, 95% confidence interval 1.40–2.09, P < 0.001). Compared with the lowest tertile, patients in the highest tertile (≥ 22.6) also had a higher risk of death (HR = 1.56, 95% CI 1.25–1.94, P < 0.001). Restricted cubic spline analysis suggested a linear association between NPAR and mortality risk. NPAR showed a statistically significant but modest improvement in discrimination compared with neutrophil percentage (AUC 0.62 vs. 0.59, P = 0.006) and albumin (0.62 vs. 0.57, P < 0.001). Elevated NPAR is independently associated with higher in-hospital mortality in patients with acute aortic dissection. As an easily obtainable marker reflecting both inflammatory status and nutritional condition, NPAR may provide supplementary prognostic information for risk stratification. However, its discriminatory ability is modest, and it should be considered as an adjunct to established clinical risk factors rather than a standalone tool for clinical decision-making.