Peripheral Neutrophil-to-Lymphocyte Ratio in stable state Bronchiectasis as a Marker of Disease Severity: A Retrospective Cohort Study in North Taiwan

Background We aimed to evaluate the clinical relevance of the neutrophil-to-lymphocyte ratio (NLR) and the severity scoring systems in the potential diagnostic and prognostic value in stable non-CF bronchiectasis. Methods This retrospective study was conducted from 146 patients with stable non-CF bronchiectasis between January 2017 and August 2025. Participants were stratified into two groups based on the optimal AUC-derived NLR cut-off value of 2.76. Results Patients with NLR ≥ 2.76 had significantly higher proportions of current and former smokers ( p  = 0.031) and higher smoking amounts (packs/year) ( p  = 0.031). The FEV1% was significantly higher in the NLR < 2.76 group ( p  = 0.021). The AUC between BSI, FACED and NLR were 0.716 vs. 0.706 ( p  = 0.025) and 0.706 vs. 0.636 ( p  = 0.032), respectively. Severe BSI scores were significantly different for survival rate (HR = 0.386, p  = 0.008). The moderate cases of FACED score showed a significant difference (HR = 0.238, p  = 0.004) when compared with mild scores. NLR ≥ 2.76 patients demonstrated a higher death rate than NLR < 2.76 (HR = 0.514, p  = 0.078). Conclusions NLR is associated with non-cystic fibrosis bronchiectasis severity and mortality and may help predict survival rate that may serve as potential predictors of clinical outcomes in stable non-CF bronchiectasis.