The neutrophil-to-albumin ratio is associated with in-hospital mortality in patients with cirrhosis and pneumonia: a multicenter retrospective cohort study

Patients with cirrhosis are highly susceptible to pneumonia, which significantly increases mortality. Existing prognostic scores have limitations in capturing the dual burden of systemic inflammation and impaired hepatic synthesis. The neutrophil-to-albumin ratio (NAR), a composite biomarker reflecting both inflammatory activity and nutritional status, may offer more comprehensive risk stratification in this population. This multicenter retrospective cohort study enrolled 504 hospitalized patients with concurrent cirrhosis and pneumonia from five centers between November 2013 and December 2024. The primary outcome was in-hospital mortality. Patients were stratified by admission NAR tertiles. Multivariable logistic regression models were used to assess the independent association between NAR (analyzed as both continuous and categorical variable) and mortality, with progressive adjustment for demographics, comorbidities, and key laboratory parameters. Sensitivity analyses, including E-value calculation and subgroup analyses, were performed. Mediation analysis evaluated the role of white blood cell count (WBC). The cohort’s mean age was 64.7 ± 12.4 years, with 64.9% males. Higher NAR was associated with worse liver function (Albumin-Bilirubin grade, Model for End-Stage Liver Disease score), greater pneumonia severity (CURB-65), and elevated inflammatory markers. In-hospital mortality was significantly higher in the highest NAR tertile (14.9% vs. 5.4% in the lowest, P < 0.002). After full adjustment, each unit increase in NAR was associated with a 2.23-fold higher mortality odds (OR = 2.23, 95% CI: 1.25–4.00, P = 0.007). Patients in the highest tertile had 2.48 times the odds of death compared to the lowest (OR = 2.48, 95% CI: 1.08–5.70, P = 0.032), with a significant dose-response trend (P = 0.017). Sensitivity analyses confirmed robustness. Mediation analysis indicated that approximately 50% of NAR’s effect on mortality was mediated through WBC. Admission NAR is strongly and independently associated with in-hospital mortality in cirrhotic patients with pneumonia, integrating systemic inflammation and nutritional status. This readily calculable biomarker may enhance risk assessment in this high-risk population and warrants prospective validation. Chinese Clinical Trial Registry, ChiCTR2500097772. Registered 25 February 2025.