The relationship between the ratio of lactate to albumin (LAR) and the prognosis of patients with acute exacerbation of chronic obstructive pulmonary disease (AECOPD)

Purpose Acute exacerbation of chronic obstructive pulmonary disease (AECOPD) is a major cause of hospitalization and mortality. Inflammatory responses may play a crucial role in this process. The lactate-to-albumin ratio (LAR), a novel inflammatory biomarker, has been linked to adverse outcomes in various diseases, but its prognostic value in AECOPD remains unclear. This study aimed to evaluate the association between LAR and both in-hospital and follow-up mortality in AECOPD patients. Patients and methods This was a single-center retrospective cohort study using data from the MIMIC-IV (v3.0) database. The primary outcome was in-hospital all-cause mortality; the secondary was follow-up mortality. Kaplan–Meier curves compared survival across four LAR groups. Cox proportional hazards models and restricted cubic splines assessed associations between LAR and outcomes. Subgroup analyses include age (< 60 years or ≥ 60 years), the presence or absence of pneumonia, lung cancer, and other diseases to further examine consistency across patient populations. Results A total of 919 patients were included, with a mean age of 69.6 years. Of these, 171 (18.6%) died during hospitalization and 534 (58.1%) during follow-up. Higher LAR levels were significantly associated with increased mortality (log-rank P < 0.05). Multivariable Cox analysis confirmed LAR as a predictor of in-hospital mortality (HR = 1.48, 95% CI 1.18–1.85, P = 0.001) and follow-up mortality (HR = 1.29, 95% CI 1.10–1.52, P = 0.002). Findings were consistent across the majority of subgroups. Conclusions Elevated LAR levels were associated with increased in-hospital and follow-up mortality in AECOPD patients. LAR may serve as a simple and valuable supplementary biomarker for risk stratification and disease severity assessment.