A Case-Control Study of Fragility Fracture Risk among Inflammatory Bowel Disease Patients

Abstract

Purpose: To determine whether inflammatory bowel disease (IBD) patients have an increased risk of vertebral and non-vertebral fragility fractures compared to a non-IBD population. Methods: Fracture cases were defined as patients ≥18 years of age with a newly diagnosed vertebral or non-vertebral fragility fracture between 1/1/01 and 6/30/03 (index date) in the Ingenix Lab/Rx Database™ and between 1/1/01 and 12/31/02 (index date) in the Medstat MarketScan Database®. We identified fragility fractures by only including patients with closed fractures, and excluding patients with a record of malignant neoplasm and/or trauma ‘E codes’ at any point. A vertebral fracture diagnosis was validated with a record of a radiologic examination ±15 days from the diagnosis date. For each case, 1 control patient with no record of a vertebral or non-vertebral fracture was randomly selected, and matched by age (±2 years), gender, and calendar year. IBD patients were identified by having a diagnosis of ulcerative colitis or Crohn's disease or ≥2 5-ASA prescriptions in the year prior to the index date. Odds ratios were computed using conditional logistic regression models and adjusting for age, gender, and glucocorticosteroid use in the 12 months prior to the index date. Results: After combining both databases, a total of 141,266 fragility fracture cases and 141,266 matched controls were identified. Of these, 1,126 fracture cases and 696 controls were diagnosed with IBD. Overall, IBD patients appeared to have a 62% higher risk for fracture (OR = 1.62, 95% CI = 1.47–1.78). After adjusting for age, gender, and glucocorticosteroid use, the risk remained elevated (adjusted OR = 1.46, 95% CI = 1.33–1.61). Based on crude odds ratios, ulcerative colitis patients were 55% more likely to develop a fracture compared to non-IBD patients (OR = 1.55, 95% CI = 1.33–1.79), and Crohn's disease patients were more than 70% more likely to have a fracture versus non-IBD patients (OR = 1.71, 95% CI = 1.46–2.00). Conclusions: The results of this case-control study suggest an increased risk of fragility fractures among IBD patients, even after adjusting for glucocorticosteroid use. It will be important to assess the effect of fracture-prevention treatment in an IBD population.