Association between neutrophil percentage-to-albumin ratio and mortality in Hemodialysis patients: insights from a prospective cohort study

BACKGROUND: The neutrophil percentage-to-albumin ratio (NPAR) emerges as a novel inflammation marker, demonstrating prognostic ability in a variety of cardiovascular diseases. However, its impact on mortality among patients undergoing maintenance hemodialysis (MHD) remains uncertain. Our research aims to determine whether NPAR is a reliable predictor of mortality in MHD patients. METHODS: A total of 1803 MHD patients were recruited in this prospective cohort. Patients were stratified into three groups based on baseline NPAR levels. The association between NPAR and all-cause and cardiovascular mortality was evaluated using multivariate Cox proportional risk model and sensitivity analysis. NPAR's predictive performance was assessed using the receiver operating characteristic (ROC) curve, compared to several conventional biomarkers, including the neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), neutrophil count, and serum albumin. The area under the curve (AUC) values of NPAR and these biomarkers were compared using the DeLong's test. RESULTS: Throughout a median follow-up period of 28 months, 239 (13.3%) patients died, with 91 (5.0%) dying of cardiovascular disease. Both all-cause mortality and cardiovascular mortality exhibited remarkably higher within the high NPAR group compared to the middle and low NPAR groups in the multivariate Cox regression analysis. The adjusted hazard ratio was 1.550 (95% CI: 1.110-2.166, P = 0.010) for all-cause mortality and 1.844 (95% CI: 1.058-3.212, P = 0.031) for cardiovascular mortality. This association was further corroborated by sensitivity analyses. The AUC values of NPAR for all-cause mortality and cardiovascular mortality were 0.612 (95% CI: 0.572-0.652, P < 0.001) and 0.618 (95% CI: 0.557-0.678, P < 0.001), separately. The p-values for comparing NPAR's AUC with those of NLR, PLR, neutrophils, and albumin were 0.307, 0.094, 0.014, and 0.154 for all-cause mortality, and 0.879, 0.126, 0.119, and 0.596 for cardiovascular mortality. CONCLUSION: High NPAR level was independently associated with a higher increased risk of death in MHD patients.