Prognostic value of initial hemoglobin levels for neurological outcomes in patients with out-of-hospital cardiac arrest in South Korea.
Acute and critical care · 2026-05-19 · Registry study
Abstract
BACKGROUND: Previous studies suggest that lower hemoglobin (Hb) levels are associated with adverse outcomes after out-of-hospital cardiac arrest (OHCA). However, most of these were limited by small sample sizes and single-center designs. We aimed to evaluate the association between initial Hb levels and clinical outcomes after OHCA using a large multicenter registry. METHODS: This retrospective observational study analyzed prospectively collected multicenter registry data. Hb levels measured at emergency department arrival were analyzed as continuous variables with restricted cubic spline (RCS) models, which flexibly characterize dose-response relationships with unfavorable neurological outcomes and in-hospital mortality. Generalized estimating equations with a logit link were used to account for within-hospital clustering and to adjust for clinically relevant covariates. RESULTS: Lower Hb levels were independently associated with higher adjusted odds of unfavorable neurological outcomes and in-hospital mortality. RCS analyses showed a statistically significant overall association between Hb levels and both outcomes after multivariable adjustment (overall P<0.001). The adjusted odds of adverse outcomes increased progressively with decreasing Hb levels. Cluster-adjusted analyses using generalized estimating equations yielded consistent results. CONCLUSIONS: Initial Hb levels were independently associated with neurological outcomes and in-hospital mortality after OHCA. Modeling Hb as a continuous variable showed a graded association across the Hb spectrum. These findings highlight the prognostic relevance of baseline Hb levels.