Factors associated with sarcopenia in elderly patients with type 2 diabetes mellitus.

Background and aims: Sarcopenia is a common geriatric syndrome that substantially impairs physical function, mobility, and quality of life in older patients with type 2 diabetes mellitus. However, evidence regarding factors associated with sarcopenia in this population remains fragmented and inconsistent, and previous studies have often included mixed-age populations or provided limited quantitative synthesis specifically focused on older adults. Therefore, this systematic review and meta-analysis aimed to comprehensively identify and quantify the associations between clinical factors and sarcopenia in older patients with type 2 diabetes mellitus, thereby providing age-specific evidence for clinical assessment, early identification, and individualized management. Methods: Relevant studies examining factors associated with sarcopenia in older patients with type 2 diabetes mellitus were systematically searched in six databases: PubMed, Web of Science, Embase, the Cochrane Library, CNKI, and Wanfang Data. The search covered the period from database inception to January 2026. Study characteristics, participant characteristics, potential associated factors, and sarcopenia-related outcomes were extracted. The methodological quality of the included cross-sectional studies was assessed using the AHRQ checklist. Meta-analyses were conducted using Review Manager version 5.3. Continuous variables were pooled using mean differences or standardized mean differences, and dichotomous variables were pooled using odds ratios. Publication bias and small-study effects were assessed using funnel plots and Egger's regression test when at least 10 studies were available for a given outcome. For outcomes with substantial heterogeneity, REML-based 95% prediction intervals and exploratory univariable meta-regression analyses were conducted when sufficient data were available. The certainty of evidence for each pooled outcome was assessed using the GRADE approach. Results: A total of 19 cross-sectional studies involving 4,727 older patients with type 2 diabetes mellitus were included. The included studies were of moderate to high methodological quality, with no low-quality studies identified. Sarcopenia was diagnosed using different criteria, including the Asian Working Group for Sarcopenia 2014 criteria, the AWGS 2019 criteria, the European Working Group on Sarcopenia in Older People criteria, and the revised EWGSOP2 criteria. Meta-analysis showed that patients with sarcopenia were significantly older than those without sarcopenia, and had a longer duration of diabetes, higher fasting blood glucose levels, higher HbA1c levels, lower body mass index, and lower hemoglobin levels. No statistically significant associations were observed for male sex, total cholesterol, triglycerides, HDL-C, LDL-C, serum albumin, 25(OH)D, hypertension, smoking exposure, insulin therapy, or coronary/ischemic heart disease. Although sensitivity analyses generally supported the directional stability of the main findings, substantial heterogeneity remained for several outcomes, and all REML-based 95% prediction intervals crossed the null value. Exploratory meta-regression identified geographic region as a significant moderator only for HbA1c. Egger's tests did not indicate statistically significant small-study effects for outcomes with sufficient studies. The certainty of evidence was rated as low for HDL-C, hypertension, and insulin therapy and as very low for all other pooled outcomes, primarily because of the cross-sectional study design, substantial inconsistency, and imprecision. Conclusion: In conclusion, older age, lower BMI, longer diabetes duration, higher fasting blood glucose, higher HbA1c, and lower hemoglobin levels were associated with sarcopenia in older patients with type 2 diabetes mellitus. However, the certainty of evidence was low to very low, and substantial heterogeneity and prediction intervals crossing the null value indicate that the magnitude and presence of these associations may vary across populations and clinical settings. These findings may heighten clinical suspicion during guideline-based sarcopenia assessment but should not be regarded as evidence of independent prediction, validated screening thresholds, or causality. Future prospective studies with standardized measurements and comprehensive adjustment for confounders are required. Systematic review registration: https://www.crd.york.ac.uk/prospero/, identifier CRD420261301123.