Association between neutrophil percentage-to-albumin ratio and all-cause mortality in patients with sepsis: A retrospective cohort study

Sepsis is a life-threatening syndrome caused by an imbalanced host response to infection and remains one of the leading causes of death worldwide. The neutrophil percentage-to-albumin ratio (NPAR) has recently emerged as a novel biomarker that integrates information on systemic inflammation and nutritional status. However, its role in predicting outcomes among septic patients has yet to be fully clarified. This study aimed to investigate the association between NPAR and all-cause mortality at 28-day, 90-day, and 365 day in patients diagnosed with sepsis. Using the medical information mart for intensive care-IV v3.1 database, we identified 6242 patients meeting the Sepsis-3.0 definition. Participants were categorized into tertiles based on NPAR values (Q1 < 23.8; 23.8 ≤ Q2 < 30.1; Q3 ≥ 30.1). Multivariable Cox proportional hazards regression was employed to analyze associations between NPAR and mortality. Restricted cubic spline models assessed nonlinear trends, while receiver operating characteristic curves evaluated discriminative ability. Kaplan-Meier survival analyses were performed to visualize survival differences across NPAR groups. Patients in the highest NPAR tertile (Q3) exhibited significantly greater disease severity and higher mortality at 28 days (34.03% vs 22.28%), 90 days (43.54% vs 28.93%), and 365 days (52.33% vs 37.72%) compared to those in the lowest tertile (Q1; all P < .001). After adjusting for confounders, elevated NPAR remained an independent predictor of mortality at 28 days (HR = 1.22, 95% CI: 1.06-1.39), 90 days (HR = 1.24, 95% CI: 1.10-1.40), and 365 days (HR = 1.21, 95% CI: 1.09-1.35). Restricted cubic spline analyses revealed a U-shaped nonlinear relationship between NPAR and mortality (P for nonlinearity < .001). Integrating NPAR with the sequential organ failure assessment score significantly enhanced predictive accuracy compared to sequential organ failure assessment alone (area under the curve: 0.624 vs 0.599, P < .001). Subgroup analysis indicated a more pronounced association in patients with congestive heart failure (P for interaction = .002). High NPAR levels are independently associated with increased short- and long-term mortality in sepsis. Given its simplicity and cost-effectiveness, NPAR could be a useful marker for early risk assessment and clinical decision-making in septic populations.