Background Inflammatory Bowel Disease (IBD) is a known risk factor for developing low bone mineral density (BMD) osteoporosis, due to malabsorption and treatment with steroids. These patients are more susceptible to fragility fractures. Though the percentage of such fractures is low, they can be associated with impaired mortality and morbidity. The difficulty lies in early detection of patients at an increased risk of fractures. Currently the diagnosis of osteoporosis and predictions of fracture risk are calculated assessing patient BMD on dual energy X-ray absorptiometry (DEXA). However, previous studies suggest that despite a decreasing BMD being significantly associated with an increased risk of fracture, its measurement alone is fairly restricted in predicting them; other patient factors must also be brought into consideration (1).
Objectives To identify specific factors which may assist in the prediction of fragility fractures in a cohort of patients diagnosed with IBD.
Methods Patients referred to a DEXA scan in the North West of England were identified and those with a referral reason of IBD were studied. Factors measured at BMD scanning include patient age, height, weight, lumbar and femoral head bmd, BMI, smoking history, alcohol use, family history of fractures, steroid exposure, rheumatoid arthritis and secondary osteoporosis. Patients where assorted into cases and controls after adjusting for age and gender. They were then analysed using T tests for continuous variables and Chi squared tests for categorical variables. Univariate and multivariate logical regression models were then utilised to identify factors predicting fractures.
Results 938 patients were identified of which 721 (76.9%) were female with an average age of 58 as compared to an average age of 53 in men. 274 patients (29%) had fractures of which 238 were females (87%), at an average age of 63 compared to 60 in men. Men were shown to have a greater risk of fractures. Results of the univariate analysis are shown below.
In the multivariate analysis, statistically significant variables were BMI (OR 1.05, 95% CI 1.01–1.08) and steroids (OR 0.49, 95% CI 0.35–0.69) with steroids being protective against fractures.
Conclusions In the univariate analysis several risk factors are shown to be associated with fractures. These include femoral neck BMD, steroid use, lumbar BMD and the patient age at the time of the scan. The multivariate analysis showed that the biggest predictor after adjusting for age and gender is steroids and BMI with steroids being protective.
Marshall D, Johnell O, Wedel H. Meta-analysis of how well measures of bone mineral density predict occurrence of osteoporotic fractures. BMJ. 1996;312(7041):1254–9.
Disclosure of Interest None declared