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P075. Can clinical parameters of disease severity help to predict risk for osteoporosis in inflammatory bowel disease?

O. Kelly, S. Long, M. Forry, S. Patchett, F.E. Murray

Beaumont Hospital/Royal College of Surgeons in Ireland, Dublin, Ireland

Introduction: Patients with inflammatory bowel disease are susceptible to osteoporosis for a number of reasons, including low body mass index, steroid usage but also independent disease activity. However, despite availability of management guidelines, early identification of patients at risk of osteoporosis and therefore in need of early screening and treatment remains challenging. This study aimed to look at a set of commonly used clinical and serological parameters for disease activity and assess association of these markers with development of metabolic bone disease in IBD.

Method: Patients identified from a computerised IBD database in a tertiary referral centre who had undergone DEXA (Dual X-ray Absorptiometry) scanning were eligible for inclusion. The osteoporosis group included all those with Z scores of <−2. This group was compared with age and sex-matched IBD controls with defined normal bone mineral density. Disease site, duration, endoscopic severity, inflammatory markers, steroid, immunemodulation or biologic usage and incidence of surgery were recorded. Independent risk factors for osteoporosis were also identified (eg. age, gender, previous fracture). Descriptive statistics are reported as % median with interquartile range. Categoric data were compared using Fisher's exact test. Mann-Whitney test was used to compare paired non-parametric data. Odds ratios, relative risk and likelihood ratios were calculated. p values <0.05 were deemed significant.

Results: 1014 IBD patient records were examined. 498 patients with reported DEXA scans were identified (49%). Of these, 18.6% patients had osteoporosis (giving an overall prevalence of 9.4%). 34.4% had normal scans and controls were taken from this cohort. Median age in the osteoporosis group was 56 years (IQR 27–67), compared to 41 (36–49) in the general IBD population. The distribution of UC and Crohn's Disease was similar in both groups. 18.3% of the osteoporotic group had experienced one or more fractures compared to <1% of the normal group (p < 0.001). Disease site, surgery rates and use of immunemodulation or biologics were not statistically different. The osteoporosis group were 3-fold more likely to have endoscopically severe disease. Disease duration was 11.86 ±7.026 years (mean ±SD) compared to 8.58±4.41 years in controls (p = 0.0052). This may of course be a surrogate marker for low body mass index or increased exposure to steroids. Interestingly, 27.7% of the osteoporosis group had persistent elevation of CRP, independent of disease severity and significantly different to the normal cohort (p < 0.01) with a relative risk of 2.62 (95% CI: 1.3–5.9).

Conclusion: Clinical markers predictive for osteoporosis in this cohort include endoscopic severity, persistently elevated CRP and increased disease duration, indicators of more aggressive disease and increased likelihood of extra-intestinal complications such as osteoporosis. Given these data, there is scope for development of a simple scoring system using logistic regression to aid clinicians in assessing need for prophylactic treatment and screening in this at-risk population.