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P214 Low bone mineral density in inflammatory bowel disease patients

C. Eddy1, S. Stanton2, K. Subramaniam1,3

1Australian National University Medical School, Australian National University, Canberra, Australia, 2Department of Endocrinology, Canberra Hospital, Canberra, Australia, 3Gastroenterology and Hepatology Unit, Canberra Hospital, Canberra, Australia

Background

Low bone mineral density (BMD) is an extra-intestinal manifestation and common complication of inflammatory bowel disease (IBD). There are many risk factors thought to contribute to this reduction in BMD but there is no clear consensus on screening for low BMD in IBD. This study was performed to determine the prevalence, screening strategy and risk factors for low BMD in the IBD population at a single tertiary centre.

Methods

Patients with IBD attending a single tertiary centre were included. Electronic medical records were reviewed and data on demographics, BMD assessments with dual-energy X-ray absorptiometry (DXA) scans as well as risk factors for low BMD were collected. BMD classification was in line with the World Health Organisation definitions. Multivariate analysis with logistic regression was used to compare variables.

Results

There were a total of 553 IBD patients; 281 (50.8%) were females and 364 (65.8%) had Crohn’s disease. Of the total cohort, 245 (44.3%) had a DXA scan performed. Of the 245 patients that had a DXA scan, 101 (41.2%) were defined as osteopenic, 16 (6.5%) were defined as osteoporotic and 128 (52.2%) had normal BMD. The average age of the DXA cohort at the time of scanning was 39 years old. There were 124 (50.6%) females and Crohn’s disease was present in 70.2% (n = 172) of the DXA cohort. The average BMI of the DXA cohort was 26.5 with a range of 16.5 to 59.1. The majority (n = 173; 70.6%) of the DXA cohort had reportedly never smoked with the rest being either current smokers (n = 35; 14.3%) or ex-smokers (n = 37; 15.1%) at the time of their scan. Follow up DXAs occurred in 34.6% of those 245 patients with an average time between scans of 4.6 years. In terms of the risk factors, gender was not found to be a significant risk factor (p = 0.085) along with the type of IBD (p = 0.174), steroid usage 20 mg/day in the 2 years prior to DXA scan (p = 0.886) and smoking history (p = 0.195). However, patients aged ≥50 years were more likely to have low BMD than patients aged <50 years (65.6% vs. 41.8%, p < 0.001). Similarly patients with a BMI <25.5 were more likely to have low BMD than patients with a BMI ≥25.5 25.5 (59.7% vs. 36.5%; p = 0.001).

Conclusion

We found a high prevalence of osteopenia (41%) but osteoporosis (6.5%) was uncommon in this IBD population from a single tertiary centre. Only age ≥50 years and BMI <25.5 were found to be significant risk factors for low BMD. Screening of this population was inconsistent with only 44% of the total cohort having an initial DXA scan and 35% of those who have an initial scan having a follow-up DXA scan. Local guidelines on screening for low bone mineral density are warranted.