INHERITED DISORDERS OF COAGULATION APPEAR TO PROTECT AGAINST INFLAMMATORY BOWEL-DISEASE

Background/Aims: Crohn's disease and ulcerative colitis seem to be rar ely associated with inherited diseases of coagulation. Histological an d hematologic studies suggest that thrombotic mesenteric microvascular occlusion is involved in the pathogenesis of inflammatory bowel disea se. The aim of this study was to perform a national survey to determin e the prevalence of inflammatory bowel disease among patients with inh erited disorders of coagulation. Methods: Using a postal and telephone questionnaire survey sent to directors of all 129 hemophilia centers in the United Kingdom, the number of patients with inflammatory bowel disease and either hemophilia or von Willebrand's disease was determin ed. The expected number of cases of inflammatory bowel disease in this population was estimated using published data. Results: Of 6433 patie nts with hemophilia and 3129 patients with von Willebrand's disease, 4 cases of Crohn's disease were reported compared with expected 11.97-1 6.58 cases (standardized morbidity ratio, 0.33-0.24; 95% confidence in terval, 0.90-0.01; P < 0.05). Ulcerative colitis also occurred signifi cantly less frequently than expected: 9 observed cases in comparison w ith expected 19.43-31.35 cases (standardized morbidity ratio, 0.46-0.2 9; 95% confidence interval, 0.91-0.01; P < 0.025). Conclusions: This e pidemiological study provides further evidence that thrombosis and vas cular occlusion may be important in the pathogenesis of inflammatory b owel disease.