Background: The etiology of Crohn's disease, an illness protean in its manifestations, may be better resolved through studies involving more homogenous subgroups of patients. Because a strong genetic influence exists, family history of inflammatory bowel disease may be a useful variable for patient classification if patients with familial and sporadic Crohn's disease are clinically different. Our study attempted to define any possible differences.
Methods: The medical records of 552 patients were reviewed, and patients were classified according to guidelines of the Vienna Classification. Patients were then divided based on family history of inflammatory bowel disease, and the familial and sporadic groups were compared.
Results: Overall, 422 (78.9%) patients were diagnosed before age 40 years (A1) and 114 (21.1%) at age 40 years or older (A2). There were 141 (26.3%) patients with disease involving the terminal ileum only (L1), 211 (39.4%) in the colon only (L2), 117 (21.9%) in the terminal ileum and colon (L3), and 66 (12.3%) in the upper gastrointestinal tract (L4). Disease behavior, as determined at the time of last visit or telephone contact, was nonstricturing, nonpenetrating (B1) in 149 (27.9%) patients, stricturing (B2) in 50 (9.3%) patients, and penetrating (B3) in 336 (62.8%) patients. Comparisons among the groups of 53 patients with first-degree relatives only, the 96 patients with either first-, second-, or third-degree relatives (familial CD group), and the 439 patients with sporadic disease demonstrated no differences in sex, age at diagnosis, or disease location. There was a difference in disease behavior between the familial and sporadic groups (p = 0.048) that failed to exist when nonstricturing, nonpenetrating cases were excluded. No such difference was observed between the first-degree relatives only group and the sporadic group (p > 0.10).
Conclusions: Using the Vienna Classification, familial and sporadic Crohn's disease differed only in disease behavior. However, this difference failed to exist after patients with nonstricturing, nonpenetrating disease were excluded. Therefore, familial and sporadic groups appear to be quite similar clinically, and family history does not appear to be a variable useful for disease subclassification.