Abstract
Chronic obstructive pulmonary disease (COPD) is a leading cause of morbidity and mortality worldwide. Exacerbations significantly contribute to poor clinical outcomes and increased mortality. Biomarkers such as neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), and eosinophil-to-lymphocyte ratio are useful in predicting the prognosis of COPD exacerbations. This study aimed to evaluate the predictive value of the lactate dehydrogenase-to-albumin ratio (LAR), along with NLR, PLR, and eosinophil-to-lymphocyte ratio, for poor clinical outcomes and mortality in patients hospitalized due to COPD exacerbations. We retrospectively analyzed 216 patients hospitalized for COPD exacerbations between 2018 and 2023. Demographic data, comorbidities, laboratory findings, and clinical outcomes, including mortality, noninvasive mechanical ventilation (NIMV), intensive care unit (ICU) admission, and prolonged hospitalization, were evaluated. Multivariate logistic regression and receiver operating characteristic curve analyses were used to examine the relationships between biomarkers and clinical outcomes. Both NLR and PLR were significantly increased in patients admitted to the ICU (P = .008 and P = .048) and in those who died (P = .005 and P = .019). Deceased patients also had higher levels of urea and blood urea nitrogen (P = .008 and P = .007) and lower lymphocyte counts (P = .012). The risk of mortality was higher in patients with longer hospital stays (odds ratio [OR]: 1.326; P = .025), those requiring NIMV (OR: 20.62; P = .035), patients with elevated blood urea nitrogen levels (OR: 1.126; P = .015), and in those with lower lymphocyte counts (OR: 0.996; P = .039). Receiver operating characteristic analysis showed that NLR predicted mortality with an area under the curve of 0.794 (95% confidence interval: 0.682-0.905; cutoff: 11.84; sensitivity: 75%; specificity: 80.8%, P = .005) and PLR with an area under the curve of 0.745 (95% confidence interval: 0.635-0.855; cutoff: 256.53; sensitivity: 75%; specificity: 70.7%, P = .019). LAR levels were significantly higher in patients who required oxygen therapy (P = .004) and NIMV (P = .049). In this study, NLR and PLR were significantly associated with ICU admission and in-hospital mortality. Although LAR was higher in patients requiring oxygen therapy and NIMV, it was not significantly associated with mortality; therefore, its prognostic value remains uncertain. Future research should focus on prospective multicenter cohorts and incorporate dynamic or serial biomarker monitoring to improve prognostic accuracy and better characterize the temporal behavior of these markers.