Should we monitor vitamin B12 levels in patients who have had end-ileostomy for inflammatory bowel disease?

Abstract

We examined whether vitamin B12 levels are low following surgery in those patients who have had end-ileostomy for inflammatory bowel disease. This prospective observational study used the database of a university teaching hospital to identify patients with inflammatory bowel disease with an end-ileostomy constructed more than 30 months previously. Precise diagnosis, disease distribution and details of their surgery were collected from case notes of the 39 eligible patients (18 Crohn's disease, 17 ulcerative colitis, 4 indeterminate colitis). Mean duration since ileostomy formation was 12.53 years. Patients found to be vitamin B12 deficient underwent further investigations to ascertain the cause of their vitamin B12 deficiency (<150 ng/l). There was no significant difference between serum vitamin B12 levels in patients with Crohn's disease and those in patients with ulcerative colitis following end ileostomy formation. Two patients (5.1%) were identified as having vitamin B12 deficiency. One of these had had a panproctocolectomy for Crohn's disease, followed by subsequent resection for ileal obstruction and ongoing small intestinal disease. The other had had colectomy for ulcerative colitis, in whom no cause other than the ileostomy was found for the vitamin B12 deficiency. There was no significant correlation between serum vitamin B12 levels and duration of ileostomy overall or in the disease subgroups. We do not recommend routine screening for vitamin B12 deficiency in this group of patients unless they have undergone additional small bowel resection or have ongoing small bowel inflammation.