Abstract
BACKGROUND: Predicting outcomes for out-of-hospital cardiac arrest (OHCA) patients remains challenging. We aimed to evaluate the association between the lactate/albumin ratio (LAR) upon hospital arrival and neurological outcomes in OHCA patients. METHODS: This multicenter, retrospective, nationwide observational study was based on data from the JAAM-OHCA registry, including 28,098 adults with non-traumatic OHCA from 140 emergency medical centers across Japan (June 2014 to December 2021). Receiver-operating characteristic curves assessed the predictive ability of LAR, lactate, and albumin levels. A reference model based on age, sex, witnessed arrest, initial cardiac rhythm, and time from call to hospital arrival was compared with models including LAR, lactate, or albumin levels. The primary outcome was a favorable neurological outcome at 30 days, with a secondary outcome at 90 days. Subgroup analyses were conducted among admitted patients and those who received active post-resuscitation treatments. RESULTS: Among the 28,098 patients, 1421 (5.1%) achieved favorable neurological outcomes at 30 days. We demonstrated that LAR had a significantly higher area under the curve than either lactate or albumin for predicting both 30- and 90-day outcomes (all p < 0.001), and better predictive value than either marker when added to the reference model. However, in the subgroup analysis of admitted patients, the statistical difference between LAR and albumin was no longer apparent. CONCLUSION: The lower LAR upon hospital arrival was independently associated with a favorable neurological outcome in OHCA patients. However, its utility may vary depending on patient background, and further studies are needed to establish its clinical relevance.