ELEVATED METHYLMALONIC ACID AND TOTAL HOMOCYSTEINE LEVELS SHOW HIGH PREVALENCE OF VITAMIN-B-12 DEFICIENCY AFTER GASTRIC-SURGERY

Objective: To determine the prevalence of vitamin B-12 deficiency in p atients who have had gastric surgery. Design: Cross-sectional study. S etting: Philadelphia Veterans Affairs Medical Center. Participants: 61 patients who had had gastric surgery and 107 controls. Measurements: Serum levels of vitamin B-12 folate, methylmalonic acid, and total hom ocysteine measured before and after treatment in participants with vit amin B-12 deficiency. Vitamin B-12 deficiency was defined as one of th e following: 1) a serum vitamin B-12 level less than 221 pmol/L and an elevated methylmalonic acid level; 2) a serum vitamin B-12 level less than 221 pmol/L and an elevated total homocysteine level that decreas ed with vitamin B-12 treatment; or 3) in patients unavailable for trea tment, a serum vitamin B-12 level less than 221 pmol/L, a folate level greater than 9 nmol/L, and an elevated total homocysteine level. Resu lts: Study patients and controls were similar in age, sex, and racial distribution. Nineteen patients (31%) and 2 controls (2%) had vitamin B-12 deficiency (P < 0.001). Twelve (63%) of the 19 vitamin B-12-defic ient patients had elevated total homocysteine levels. In all participa nts with vitamin B-12 deficiency who received treatment (15 of 21). me thylmalonic acid and total homocysteine levels decreased substantially , confirming the deficiency before treatment. Conclusion: Patients who have had gastric surgery have a high prevalence of vitamin B-12 defic iency. Prompt recognition and treatment of the deficiency with resulta nt normalization of elevated total homocysteine and methylmalonic acid levels may prevent the development of cardiovascular, hematologic, an d neurologic abnormalities. Our data support both frequent screening a nd vitamin B-12 replacement therapy in patients who have had gastric s urgery and have serum vitamin B-12 levels less than 221 pmol/L.