Is there an association between tendinopathy and diabetes mellitus? A systematic review with meta-analysis

Background Musculoskeletal symptoms limit adherence to exercise interventions for individuals with type 2 diabetes. People with diabetes may be susceptible to tendinopathy due to chronically elevated blood glucose levels. Therefore, we aimed to investigate this potential association by systematically reviewing and meta-analysing case-control, cross-sectional, and studies that considered both of these conditions. Methods Nine medical databases and hand searching methods were used without year limits to identify all relevant English language articles that considered diabetes and tendinopathy. Two authors applied exclusion criteria and one author extracted data with verification by a second author. Meta-analysis was conducted using a random effects model. Results were expressed as odds ratio (OR), mean difference or standardised mean difference with a confidence intervals (95% CI). Heterogeneity was assessed by I-2. Findings 31 studies were included in the final analysis of which 26 recruited people with diabetes and five recruited people with tendinopathy. Tendinopathy was more prevalent in people with diabetes (17 studies, OR 3.67, 95% CI 2.71 to 4.97), diabetes was more prevalent in people with tendinopathy (5 studies, OR 1.28, 95% CI 1.10 to 1.49), people with diabetes and tendinopathy had a longer duration of diabetes than people with diabetes only (6 studies, mean difference 5.26 years, 95% CI 4.15 to 6.36) and people with diabetes had thicker tendons than controls (9 studies, standardised mean difference 0.79 95% CI 0.47 to 1.12). Interpretation These findings provide strong evidence that diabetes is associated with higher risk of tendinopathy. This is clinically relevant as tendinopathy may affect adherence to exercise interventions for diabetes.