Diabetes mellitus and risk of deep vein thrombosis after total knee replacement: a meta-analysis of cohort studies.

The impact of pre-existing diabetes on the development of deep vein thrombosis (DVT) remains unclear. We performed a meta-analysis of cohort studies to evaluate the risk of DVT in patients with and without pre-existing diabetes. We searched Pubmed, Embase, and Cochrane databases from the inception to December 2014 for cohort studies assessing the effect of diabetes on the incidence of DVT. Pooled odds ratio (OR) with 95% confidence interval (CI) was calculated using random- or fixed-effect models. Six cohort studies were included in this meta-analysis. A fixed-effects model meta-analysis showed that pre-existing diabetes was associated with an increased risk of DVT (OR 1.36; 95% CI 1.07-1.72; P=0.01), with moderate heterogeneity among the studies (I(2) =46.2; P=0.10). When patients were divided into two subgroups based on the method of screening DVT, there was no significant heterogeneity in each subgroup. Our meta-analysis suggested that pre-existing diabetes was associated with an increased risk of DVT after total knee replacement. However, the result should be interpreted with caution because of the potential bias and confounding in the included studies.