Association of Body Mass Index and Hypoglycaemia with Mortality Rates Among Sepsis Patients: A Retrospective Sub-Analysis of the FORECAST Study

Background: Hypoglycaemia at admission is associated with high mortality in sepsis patients. The association of hypoglycaemia and body mass index (BMI) with mortality in sepsis patients has not been clarified. We aimed to assess the influence hypoglycaemia at admission on mortality in sepsis patients according to BMI categories.Methods: This was a secondary analysis of a multicentre, prospective cohort study of 59 intensive care unit in Japan. The study included 1,184 patients (age ≥16 years) with severe sepsis; the diagnosis was made based on the Sepsis-2 criteria. After excluding patients with missing data of glucose level, BMI, or survival at discharge, patients were divided into groups according to the initial blood glucose level, 2. The main outcome measure was in-hospital mortality. A multivariate logistic regression model was used to examine the association between hypoglycaemia and in-hospital mortality. BMI category-by-hypoglycaemia interactions were evaluated to assess the heterogeneity of the impact of hypoglycaemia on in-hospital mortality across BMI categories.Results: In total, 1,103 patients, including 65 patients with hypoglycaemia, were analysed. Among patients with hypoglycaemia, 13 had low, 38 had normal, and 14 had high BMI. Patients with hypoglycaemia showed higher in-hospital mortality (18/38, 47.4%) than those without hypoglycaemia (119/584, 20.4%) in the normal BMI group but not in the low and high BMI groups. In the multivariate logistic regression model, hypoglycaemia was not significantly associated with higher mortality in all patients (odds ratio [OR] 1.41; 95% confidence interval [CI] 0.77–2.58). However, there was a significant interaction between patients with normal BMI and hypoglycaemia on in-hospital mortality but not between patients with low or high BMI and hypoglycaemia (OR 2.32, 95% CI 1.05–5.07), and p for interaction: 0.0476).Conclusions: Hypoglycaemia at admission in sepsis patients was associated with high mortality in patients with normal BMI, but not in those with low or high BMI. This association may be used as a prognostic marker in sepsis patients.