Impact of diabetes mellitus on mortality in patients with acute exacerbation of chronic obstructive Pulmonary disease: a meta-analysis and systematic review

Background As one of the most prevalent comorbidities in chronic obstructive pulmonary disease (COPD), diabetes mellitus has drawn growing attention for its potential impact on clinical outcomes in acute exacerbation of COPD (AECOPD). However, the association between diabetes and mortality risk in AECOPD remains controversial. This meta-analysis synthesized available evidence to quantify the effect of diabetes on mortality among AECOPD patients, aiming to provide an evidence-based foundation for clinical risk stratification and individualized intervention. Methods We systematically searched PubMed, Embase, Cochrane Library, Web of Science, CNKI, and Wanfang databases up to March 2026 for cohort or case-control studies investigating the association between diabetes and mortality in AECOPD patients. Two researchers independently conducted literature screening, data extraction and quality evaluation. The Newcastle-Ottawa Scale (NOS) was used to assess risk of bias. Meta-analysis was performed using Stata 14.0 software. The hazard rations (HR) was used to combine the effect size, and corresponding 95% confidence interval (CI) was computed. Results A total of 9 studies were included, involving 23,883 participants. In the univariate model, diabetes increased the mortality risk of patients with AECOPD (HR = 1.45, 95%CI (1.19,1.77), P 0.0001), whereas no significant association was observed in multivariate analysis (HR = 1.50, 95% CI (0.45, 5.00), P = 0.513). Subgroup analysis showed that diabetes increased mortality risk in hospitalized AECOPD patients but not in those admitted to intensive care units. A significant association was found in case-control studies but not in cohort studies, and in studies with a sample size 1000 but not in smaller studies. Conclusions This meta-analysis demonstrates inconsistent associations between diabetes and mortality in AECOPD patients, which may be confounded by methodological factors and study design. Current evidence does not support diabetes as an independent risk factor for mortality in AECOPD. Further well-designed, adequately powered prospective cohort studies with rigorous adjustment for confounders are warranted to clarify the true prognostic impact of diabetes on AECOPD patients.