Thrombophilic abnormalities of natural anticoagulants in patients with ulcerative colitis

Ulcerative colitis patients have increased risk for thromboembolic events. Factors predisposing to thrombosis in ulcerative colitis are poorly defined. The aim of this study was to evaluate possible thrombophilic abnormalities in patients with ulcerative colitis.

Fifty-one patients with ulcerative colitis and 51 healthy controls were studied. Disease activity, clinical and endoscopic, was assessed by standard criteria. Plasma levels of antithrombin, protein C, free protein S and activated protein C resistance were determined in both study groups. Genetic test for factor V Leiden was performed in cases with abnormal activated protein C resistance. Parameters of inflammation and fibrinogen were additionally measured in ulcerative colitis patients.

Mean values of free protein S were significantly lower in ulcerative colitis patients (84.01 +/- 21.57) compared to healthy controls (100.17 +/- 24.7) (p < 0.001). Mean values of protein C were higher in ulcerative colitis patients (124.6 +/- 39.03) than healthy controls (100.19 +/- 19.86) (p < 0.001). No other significant differences were observed, but there was a trend towards higher prevalence of low values for antithrombin (9.8% vs. 0%, p = 0.056) and free protein S (19.6% vs. 5.9%, p = 0.072) in ulcerative colitis patients. Three ulcerative colitis patients and three healthy controls had low activated protein C resistance ratio. All these subjects were heterozygous for factor V Leiden. No correlation was observed between abnormalities in thrombophilic parameters and clinical, endoscopic or inflammatory parameters in ulcerative colitis group.

Abnormalities in natural anticoagulants are more common in ulcerative colitis patients compared to healthy controls, irrespective of disease activity. Low activated protein C resistance ratio due to factor V Leiden is not more common in ulcerative colitis patients than in healthy controls.