Oral challenge with a methionine load in patients with inflammatory bowel disease: a better test to identify hyperhomocysteinemia

BACKGROUND: Patients with inflammatory bowel disease have an increased risk of thrombosis. Hyperhomocysteinemia is one of the factors that have been related to thromboembolic complications. Patients with hyperhomocysteinemia and normal fasting homocysteine levels can be identified with an oral methionine load. We studied homocysteine levels in patients with IBD during fasting and after methionine load to determine the true prevalence of hyperhomocysteinemia and its relation with thrombotic events. METHODS: Prospective analysis of homocysteine levels in consecutive patients with IBD during fasting and 6-8 hours after an oral methionine load. Levels of folate and vitamin B12 were also determined. History of thrombotic events were recorded. RESULTS: Eighty-two patients with IBD, 56 with UC and 26 with CD were included. Eighteen patients (22%) had hyperhomocysteinemia during fasting. Mean levels of homocysteine after methionine load were 20.4 +/- 18.1 micromol/l (range, 1-79.7 micromol/l), and 43 patients (52%) had hyperhomocysteinemia (> or =20 micromol/l) after methionine load. Six patients (7.3%) had history of thrombosis. The homocysteine levels during fasting and after methionine load were significantly higher in patients with thrombotic events than in patients without thrombosis (15.5 +/- 3.7 micromol/l vs. 6.6 +/- 6.5 micromol/l; P = 0.002; 44.5 +/- 20.9 micromol/l vs. 18.4 +/- 16.5 micromol/l; P < 0.001, respectively). CONCLUSIONS: There is a higher prevalence of hyperhomocysteinemia in IBD patients than previously thought, this can be identified with an oral challenge of a methionine load. Hyperhomocysteinemia increases the risk of thromboembolic complications in patients with IBD.