Abstract
BACKGROUND: This study aimed to clarify the prognostic value of the neutrophil-to-lymphocyte ratio (NLR) in patients with acute exacerbation of idiopathic pulmonary fibrosis (AE-IPF). METHODS: Eighty-six patients diagnosed with AE-IPF were included in this single-center retrospective study. The NLR was calculated by dividing the peripheral neutrophil count by the peripheral lymphocyte count. The cut-off values of the NLR for predicting 90-day survival were determined using receiver operating characteristic curve analysis. Oxygenation deterioration on days 4 and 8 relative to that on day 1 was clinically defined. The prognostic value of NLR was evaluated using Cox proportional hazard regression analysis. RESULTS: The cut-off value of day-1, day-4, and day-8 NLRs for predicting 90-day survival was 12.13, 14.90, and 10.56, respectively. A higher day-1 NLR was a significant predictor of a poor prognosis in univariate and multivariate analyses. Survival was significantly better in patients without oxygenation deterioration on days 4 and 8 than in those with deterioration. Day-4 and day-8 NLR could predict 90-day survival in patients without oxygenation deterioration. CONCLUSIONS: Day-1 NLR was a useful predictor of 90-day survival in AE-IPF. Further, monitoring day-4 and day-8 NLRs and evaluating oxygenation deterioration may be useful for managing AE-IPF.