ObjectiveAlthough diabetes patients have a higher propensity to develop infection and sepsis, it is still controversial whether the mortality of sepsis patients is affected by diabetes (DM). We conducted a systematic review and meta-analysis to determine the relationship between diabetes and mortality in patients with sepsis.MethodsWe comprehensively searched for relevant studies in PubMed, MEDLINE, EMBASE, and the Cochrane Library database from January 2000 to December 2021. Two reviewers independently selected studies, extracted data, and assessed quality. We used random-effects modeling to calculate the summary of risk ratios and confidence interval (CI) of mortality. Study quality was assessed using NOS score, and publication bias was assessed using Egger's statistic.ResultsA total of 23 studies were included in the analyses, comprising 14,521,791 septic patients, including 2,866,429 DM patients. We stratified the in-hospital mortality data by duration for 30 days, 90 day, and mixed days. Meta-analysis of 23 studies showed slightly increased overall mortality among the patients with DM (RR, 1.12; 95% CI 1.00 - 1.25; I-2 96.1%; p = 0.000) by pooling of all data in the random effects model. Subgroup analysis did not demonstrate a statistically significant increase either in 30-day mortality (RR, 1.07; 95% CI 0.97-1.18; I-2 0.0%; p 0.963), 90-day mortality (RR, 1.00; 95% CI 0.95-1.07; I-2 0.0%; p = 0.735), or mixed-day mortality (RR, 1.16; CI 0.98-1.37; I-2 97.9%; p = 0.000). The quality of the included studies was good, and the median NOS score was 7.1 (range, 6-9).ConclusionsThis systematic review and meta-analysis of studies suggests that DM does slightly increase sepsis overall mortality, however with statistical heterogeneity. Due to the limitations of the analysis, more well-designed clinical studies are still necessary in future.