Diabetes mellitus and mortality in patients admitted to ICU with sepsis: a meta-analysis

Background: Diabetes mellitus (DM) is relatively common among patients with sepsis, yet its precise impact on mortality risk remains unclear. This study aims to explore the relationship between DM and mortality risk in sepsis patients by synthesizing existing data, thereby providing evidence for clinical management. Methods: A systematic search of PubMed, Embase, Web of Science, and Cochrane Library databases from their inception to October 20, 2025, identified observational studies evaluating the association between DM and mortality in patients with sepsis. A random-effects model was used to pool relative risks (RR) and 95% confidence intervals (CI) to assess the relationship between DM and sepsis-related mortality risk. Sources of heterogeneity were explored through sensitivity and subgroup analyses, and publication bias was assessed using the Egger test. Results: 1,209,263) were included in the analysis. The results of the meta-analysis indicate that DM is associated with an increased risk of mortality in sepsis patients [RR = 1.25, 95% CI (1.14, 1.38)]. Subgroup analyses revealed that DM is linked to a higher risk of in-hospital mortality [RR = 1.60, 95% CI (1.11, 2.31)], with stronger associations observed in specific regions and study designs. Notably, studies conducted in China [RR = 1.79, 95% CI (1.19, 2.70)], the Netherlands [RR = 1.14, 95% CI (1.12, 1.17)], and Israel [RR = 1.81, 95% CI (1.55, 2.12)], as well as cohort studies [RR = 1.25, 95% CI (1.13, 1.38)], showed more pronounced effects. Additionally, analyses based on the Sepsis-3 criteria also demonstrated a significant association between DM and increased mortality risk [RR = 1.59, 95% CI (1.24, 2.04)]. Conclusion: This meta-analysis indicates that DM is significantly associated with an increased risk of mortality in patients with sepsis, particularly with respect to in-hospital mortality. The observed association may be partially explained by DM-related pathophysiological mechanisms, such as immune dysfunction, dysregulated inflammatory responses, and the presence of chronic comorbidities. Subgroup analyses suggest that the strength of this association varies according to country, study design, and sepsis diagnostic criteria, underscoring the heterogeneity across existing studies. Systematic review registration: Registered with Prospero with registration number CRD420261279012.