P596. Altered calcium homeostasis and the disease activity in patients with Crohn's disease and ulcerative colitis
J. Beilfuss1, M. Heide2, J. Florholmen1, E. Kamycheva1, 1University Hospital of North Norway, Department of Gastroenterology, Tromsoe, Norway, 2University of Tromsoe, Faculty of Medicine, Tromsoe, Norway
Low bone mass density and osteoporosis frequently occur in patients with inflammatory bowel diseases (IBD) like Crohn's disease (CD) and ulcerative colitis (UC). It is not well established, how acute and/or chronic inflammation may influence calcium homeostasis and if there are differences in calcium levels in acute versus chronic IBD. Our aim was to identify ionized calcium levels in IBD patients with and without ongoing relapse of the disease.
Ninety-eight IBD patients, aged 17–73 were included in this prospective study, 38 with UC and 59 with CD. None of patients used prescribed calcium and/or vitamin D supplementation. The activity of the IBD was defined by using the respective activity scores, which include certain endoscopic features and also calprotectin measurements. Fifty-three patients had an active disease, and 42 subjects were in remission and were included in the final analysis. Serum calcium, ionized calcium, serum parathyroid hormone (PTH) and prealbumin were measured, when these patients visited our clinic. The ongoing treatment with TNF-alpha inhibitor was also registered.
There were significant differences in ionised calcium in patients with and without active disease (1.21±0.04 mmol/L vs. 1.23±0.04 mmol/L, P < 0.05) and prealbumin (0.25±0.07 mg/L vs. 0.27±0.05 mg/L, P < 0.05), whereas no differences in serum PTH levels between these two groups were observed. No significant correlations were demonstrated between measures of calcium homeostasis and inflammatory parameters in subjects with either active or inactive IBD. In the linear regression model, calprotectin was the strongest predictor of the disease activity, as expected [beta coefficient −0.75 (P < 0.001) in men and −0.42 (P < 0.05) in women, respectively], when adjusted for age and TNF-alpha inhibitor treatment. Ionized calcium and serum PTH did not demonstrate any significant associations with disease activity in the same regression model.
IBD patients have an altered calcium homeostasis and ionized calcium levels are significantly lower in the active disease state. That may indicate that IBD patients with frequent relapses may suffer from underestimated calcium losses and could be at higher risk of osteoporosis.