Admission lactate-to-hemoglobin ratio and mortality in critically ill patients with type 1 acute myocardial infarction: A mimic-iv database study.

BackgroundThe lactate-to-hemoglobin ratio (LHBR) integrates information on metabolic stress and oxygen-carrying capacity. This study aimed to evaluate the association between admission LHBR and mortality among critically ill patients with type 1 acute myocardial infarction (AMI).MethodsWe conducted a retrospective cohort study using the MIMIC-IV database (version 3.1) and included adult patients admitted to the intensive care unit (ICU) with type 1 AMI. LHBR was calculated from the first lactate and hemoglobin levels around ICU admission. The primary outcome was 30-day mortality; secondary outcomes were 60-, 90-, and 180-day mortality. Associations were evaluated using restricted cubic spline analyses, Cox proportional hazards regression models, and receiver operating characteristic (ROC) curve analyses.ResultsA total of 4,651 patients were included and categorized into LHBR tertiles using cutoffs of ≤0.127 (T1), >0.127-0.209 (T2), and >0.209 (T3). Restricted cubic spline analyses showed significant nonlinear associations between LHBR (as well as the natural logarithm-transformed LHBR) and all mortality outcomes (all P-nonlinear <0.05). In the adjusted purposeful selection model, both intermediate (T2) and high (T3) LHBR tertiles were associated with increased 30-day mortality compared with the lowest tertile (T1) (T2 vs T1: HR 1.32, 95% CI 1.07-1.64; T3 vs T1: HR 2.05, 95% CI 1.66-2.52). Comparable findings were observed for 60-day mortality (HRs 1.29 and 1.94), 90-day mortality (HRs 1.30 and 1.89), and 180-day mortality (HRs 1.26 and 1.75), respectively. Admission LHBR demonstrated slightly better discrimination for 30-day mortality than either lactate or hemoglobin alone.ConclusionsHigher admission LHBR was associated with increased short-term and long-term mortality in critically ill patients with type 1 AMI. Further studies are warranted to validate these findings and determine the clinical utility of LHBR in this population.