P597 Bone mineral density in patients after total proctocolectomy and pouch surgery due to Ulcerative Colitis have low bone mineral density, and low performance of DXA scans- a cross sectional study

Pfeffer-Gik, T.(1,2);Godny, L.(1,2);Ollech , J.(1,2);Wasserberg, N.(2,3);Barkan , R.(1);White, I.(2,3);Yackobovitch Gavan, M.(4,5);Kraizler, M.(1);Yanai , H.(1,2);Dotan, I.(1,2);

(1)Rabin Medical center, Division of Gastroenterology, Petah Tikva, Israel;(2)Tel Aviv University, Sackler Faculty of Medicine, Tel Aviv, Israel;(3)Rabin Medical center, Division of Surgery Colorectal Unit, Petah Tikva, Israel;(4)Schneider Children's Medical Center of Israel, The Jesse Z and Sara Lea Shafer Institute for Endocrinology and Diabetes- National Center for Childhood Diabetes, Petah Tikva, Israel;(5)Tel Aviv University, Dept. of Epidemiology and Preventive Medicine- School of Public Health- Sackler Faculty of Medicine, Tel Aviv, Israel;

Background

The reported prevalence of low bone mineral density (BMD) in patients with inflammatory bowel diseases (IBD) varies between 20-50%.  The multiple contributing factors include inflammation,use of corticosteroids, life style and diet.Patients with ulcerative colitis (UC) undergoing proctocolectomy with ilealpouch-anal anastomosis (IPAA) commonly develop pouchitis-de novo inflammation in previously normal small bowel, which may resemble Crohn's disease (CD).
We aimed to assess rate of low BMD in patients with a pouch and rate of DXA performance.

Methods

Patients after IPAA due to UC were prospectively followed; Questionnaires regarding demographic, disease course, surgery, diet and blood tests were collected biannually.
BMD was assessed by dual-energy x-ray absorptiometry(DXA).All medical records were reviewed for DXA performance within the last five years, if not found-patients were contacted and submitted the results. Low BMD was defined as T score < -1.

Results

Out of 146 prospectively followed patients, data regarding DXA was available for 114; 70 (61%) women. Median age 46 (IQR 38-67), median age at UC diagnosis 21 years (IQR 15.7-29.5), median pouch age 16 years (IQR 8.5-22.5). DXA scans were performed in 41/114 patients (36%), low BMD was noted in 68.3 %: osteopenia- 16 (39%), osteoporosis: 12 (29.3%). Patients performing DXA scan were older: 54 (IQR 42-64) vs. 45 years (IQR 31-54) (p=0.012), and were diagnosed with UC at younger age: 23 (IQR 17-29) vs. 19 years (IQR 14-26) (p=0.018)Smoking, UC duration prior to IPAA, indication for surgery, pouch age and pouchitis were comparable between patients who performed and did not perform DXA scans. In patients with low BMD- current smoking rates were higher compared to those with normal BMD:4 (14.3%) vs. 0 (p=0.008),respectively. Vitamin D levels in patients with low and normal BMD were comparable:22.8 (IQR 17.5-26) vs. 20 (IQR 16.8-21.8)ng/ml (p=0.158), respectively.  Vitamin D supplementation was comparable as well [38% vs. 60% (p=0.16)]. No differences in micronutrients consumption between the groups were noticed.

Conclusion

In a prospective cohort of patients after IPAA due to UC, approximately 36% performed DXA scans and the majority of them had low BMD, with smoking as a potential risk modifier. Due to high rates of low BMD in this population multidisciplinary advice and follow up should be provided to address the low performance of DXA scans and the abnormalities in BMD.