Effects of body composition on the procoagulant imbalance in obese patients

Obesity is associated with increased thrombotic risk and hypercoagulability whose main driver is an excess of coagulation factor VIII relative to protein C. The aims of this study were to evaluate the association between factor VIII, protein C, factor VIII-to-protein C ratio and bioimpedance parameters of body composition in obese patients. We analysed blood from 69 obese patients and 23 non-obese healthy controls. Plasma levels of factor VIII, protein C, and factor VIII-to-protein C ratio were correlated with total fat, visceral fat, and muscle mass. Compared to controls, obese patients had signifcantly higher factor VIII (110.5% vs 78.05%, p<0.001), protein C (120.99% versus 110.51%, p=0.014), and factor VIII-to-protein C ratio (0.93 versus 0.73, p=0.002). In obese patients, factor VIII correlated with body-mass index, body fat percentage, muscle mass percentage, and fat-to-muscle ratio, whereas protein C had signifcant relationships with body fat percentage, muscle mass percentage and fat-to-muscle ratio, but not with body-mass index. Factor VIII-to-protein C ratio>1 was signifcantly associated with body-mass index (odds ratio 1.08, 95% CI 1.02 to 1.14) and fat-to-muscle ratio (odds ratio 2.47, 95% CI 1.10 to 5.55). Factor VIII-to-protein C ratio strongly correlated with D-dimer levels in the overall population (rho 0.44, p<0.001) and obese patients (rho 0.41, p<0.001). In obese patients, bioimpedance measures of body fat and muscle mass percentage were associated with factor VIII and protein C. Factor VIII-to-protein C ratio was strongly associated with fat-to-muscle ratio and only modestly related to BMI.