The comorbid occurrence of other diagnoses in patients with ulcerative colitis and Crohn's disease.

OBJECTIVES: The comorbidity between inflammatory bowel disease (IBD) and other diagnoses may help to shed light on the etiology and pathophysiology of IBD. The US Vital Statistics offer the opportunity to study causes of death broken down by comorbid disease associations. The aim of this study was to analyze the presence of comorbid conditions in persons who died from ulcerative colitis or Crohn's disease.

METHODS: The numbers of deaths from ulcerative colitis and Crohn's disease were retrieved from the computerized 1991-1996 data files of the National Center for Health Statistics. Comorbid associations between other diagnosis and ulcerative colitis or Crohn's disease were expressed as age-, gender-, and race-standardized proportional mortality ratios.

RESULTS: Ulcerative colitis and Crohn's disease showed, in general, similar patterns of comorbidity. Both diseases were associated with similar sets of GI complications, such as intestinal obstruction and stasis, mucosal inflammation and infection, vascular complications, and complications related to fistula and abscess formation. Extraintestinal complications of both IBD involved disorders of the hepatobiliary system, urinary system, and various coagulopathies. Ulcerative colitis alone was found to be associated with Hirschsprung's disease and schizophrenia, whereas Crohn's disease alone was found to be related with osteoporosis and amyloidosis.

CONCLUSIONS: No completely unexplained or hitherto undescribed association was revealed. The numerous intestinal and extraintestinal complications associated with IBD serve as a reminder of the systemic nature and the resultant clinical severity of both ulcerative colitis and Crohn's disease.