Lactate dehydrogenase-to-albumin ratio predicts 30-day and 90-day mortality in glucocorticoid-treated ICU patients with pneumonia: a secondary analysis of a multicenter cohort

BackgroundGlucocorticoid therapy in pneumonia patients confounds conventional inflammatory biomarkers, hindering accurate risk stratification. The lactate dehydrogenase-to-albumin ratio (LAR), a proposed steroid-resilient index reflecting cellular injury and nutritional reserve, may offer prognostic utility in this population.MethodsThis secondary analysis of a multicenter cohort included 499 ICU patients with pneumonia receiving glucocorticoids. The optimal LAR cutoff for 30-day mortality was determined via the Youden index. Associations with 30- and 90-day mortality were assessed using multivariable Cox regression and propensity score matching (PSM), with doubly robust estimation serving as the primary analysis in the matched cohort. Incremental predictive value was evaluated using the net reclassification improvement (NRI) and integrated discrimination improvement (IDI).ResultsThe optimal LAR cutoff was 13.39. High LAR (≥13.39) was associated with significantly higher 30-day (45.8% vs. 12.1%) and 90-day (51.4% vs. 14.3%) mortality (both p < 0.001). After full multivariable adjustment, high LAR remained an independent predictor for 30-day (HR 2.07, 95% CI 1.34–3.20) and 90-day (HR 1.93, 95% CI 1.29–2.89) mortality. In the PSM cohort, the doubly robust estimate yielded consistent findings (30-day HR 2.07, 95% CI 1.34–3.21; 90-day HR 1.93, 95% CI 1.29–2.90). Sensitivity analyses treating LAR as a continuous variable and as tertiles confirmed a dose–response relationship independent of any single threshold. LAR demonstrated good discrimination (AUC ≈ 0.74) and provided significant incremental prognostic value when added to the PSI score (NRI 0.299, p = 0.048).ConclusionLAR is a simple, readily available, and steroid-resilient biomarker that independently predicts short- and mid-term mortality in pneumonia patients receiving glucocorticoids. Incorporating LAR into clinical assessment may enhance early risk stratification and guide individualized management in this challenging population.