Osteonecrosis in Inflammatory Bowel Disease: Clinical Features, Risk Factor Analysis, and Outcomes

Lay Summary This single-center, case-control study of inflammatory bowel disease patients with osteonecrosis showed that while corticosteroid use was likely a risk factor, especially among ulcerative colitis patients, other risk factors included estrogen use among Crohn's disease patients, arthropathy, and osteoporosis. Background Avascular necrosis (AVN) is a known adverse event associated with corticosteroid (CS) usage. Inflammatory bowel disease (IBD) is often treated with a CS for induction of remission. We sought to describe clinical features and outcomes of IBD patients with AVN. Methods In this retrospective, single-center, case-control study, patients with IBD who had a diagnosis of osteonecrosis, aseptic necrosis, or AVN from 1976 to 2009 were included, and each was matched with up to 2 controls (IBD but no AVN) on age, sex, IBD subtype, geographic area of residence, and date of IBD diagnosis. We abstracted risk factor data from the medical records. Conditional logistic regression was performed accounting for minor differences in age and date of first IBD visit to assess the relationship between putative risk factors and AVN, expressed as odds ratio and 95% confidence interval. Results Eighty-five patients were diagnosed with IBD-AVN and were matched with 163 controls. The mean age at AVN diagnosis was 47.5 years. AVN was diagnosed a median of 12.2 years after IBD diagnosis, and the control group was followed for a median of 15 years after IBD diagnosis to ensure that they did not have AVN. Ten percent of patients with AVN did not have any CS exposure. History of arthropathy or estrogen use in Crohn's disease and use of CS, osteoporosis, and history of arthropathy in ulcerative colitis were significantly associated with AVN. Conclusions Most patients with IBD-AVN had multifocal involvement. Most had received CS, but many patients had other risk factors including arthropathy.