The Metabolic SYNDROME and the RISK of Venous Thrombosis: RESULTS of AN Individual LEVEL Patient Meta-ANALYSIS

The metabolic syndrome (MS) is a cluster of interrelated risk factors that identify patients at increased risk of cardiovascular events. Recent studies also suggested an association between MS and venous thromboembolism (VTE). However, the role of the individual features of MS and whether MS and its features are more important than obesity alone to predict VTE remain to be established.

We performed an individual patient level meta-analysis of case-control studies comparing the prevalence of MS in patients with unprovoked VTE and in controls. MEDLINE, EMBASE databases, and abstract books were searched up to January 2010. Odds ratios (OR) and 95% confidence intervals of pooled results were calculated. The influence of individual variables (age, sex, BMI and MS) on the likelihood of VTE was compared using logistic regression analysis. Multivariate analysis was subsequently performed including the individual components of MS in the place of MS. The impact of increasing number of individual components of MS on the risk of VTE was investigated.

Four studies were identified and analyzed, for a total of 1332 patients (479 cases and 833 controls). Mean age was 53.3 and 52.7, respectively (p=n.s.), 49.5% cases and 42.4% controls were males (p=0.0003), 38.8% and 30.0% were obese (p=0.0001). MS was significantly associated with VTE (OR 1.97, 1.57–2.47), and the association linearly increased with the number of MS features (p for trend <0.001). At multivariate analysis, MS but not obesity remained associated with VTE (OR 1.92, 1.50–2.46 and 1.14, 0.88–1.47, respectively). All individual features of MS, but HDL cholesterol, were independently associated with VTE.

The results of this meta-analysis confirm the association between MS and VTE and suggest that MS (and visceral obesity defined by increased waist circumference) could be a more important predictor of VTE than obesity defined by BMI.

No relevant conflicts of interest to declare.