Predominantly L-shaped association between hemoglobin glycation index and all-cause mortality in hospitalized patients with heart failure.

Abstract

BackgroundHeart failure (HF) is closely associated with abnormalities in glucose metabolism, which substantially influence clinical outcomes. The hemoglobin glycation index (HGI), reflecting the discrepancy between observed and predicted glycated hemoglobin, has emerged as a marker of interindividual variation in glycation beyond conventional HbA1c. However, the prognostic significance of HGI in hospitalized patients with HF remains unclear.MethodsIn this retrospective cohort study, we analyzed data from the MIMIC-IV database and included 3,470 adult patients hospitalized with HF. HGI was calculated as the difference between measured HbA1c and predicted HbA1c derived from fasting plasma glucose, and participants were categorized into quartiles. The primary outcome was 365-day all-cause mortality, and the secondary outcome was 30-day all-cause mortality. Kaplan-Meier survival analysis, restricted cubic spline modeling, multivariable Cox regression, and subgroup analyses were performed to evaluate the association between HGI and mortality.ResultsAmong the 3,470 included patients, 837 (24.1%) died within 365 days after discharge. Restricted cubic spline analysis demonstrated a predominantly L-shaped association between HGI and both 30-day and 365-day all-cause mortality, with excess mortality risk mainly concentrated at low HGI values. In multivariable Cox models, compared with the lowest quartile, higher HGI quartiles were associated with significantly lower risks of both short-term and long-term mortality, supporting the particular vulnerability of patients with extremely low HGI. Subgroup analyses generally supported the robustness of these findings, although a significant interaction with diabetes status was observed for 365-day mortality.ConclusionsHGI was independently associated with short-term and long-term all-cause mortality in hospitalized patients with HF, with a predominantly L-shaped pattern observed. Excess mortality risk was mainly concentrated at low HGI values. HGI may serve as a simple and accessible marker for risk stratification in this population.