title: Elevated methylmalonic acid and total homocysteine levels show high prevalence of vitamin B12 deficiency after gastric surgery.
abstract: OBJECTIVE
  To determine the prevalence of vitamin B12 deficiency in patients who have had gastric surgery.
  
  
  METHODS
  Cross-sectional study.
  
  
  METHODS
  Philadelphia Veterans Affairs Medical Center.
  
  
  METHODS
  61 patients who had had gastric surgery and 107 controls.
  
  
  METHODS
  Serum levels of vitamin B12, folate, methylmalonic acid, and total homocysteine measured before and after treatment in participants with vitamin B12 deficiency. Vitamin B12 deficiency was defined as one of the following: 1) a serum vitamin B12 level less than 221 pmol/L and an elevated methylmalonic acid level; 2) a serum vitamin B12 level less than 221 pmol/L and an elevated total homocysteine level that decreased with vitamin B12 treatment; or 3) in patients unavailable for treatment, a serum vitamin B12 level less than 221 pmol/L, a folate level greater than 9 nmol/L, and an elevated total homocysteine level.
  
  
  RESULTS
  Study patients and controls were similar in age, sex, and racial distribution. Nineteen patients (31%) and 2 controls (2%) had vitamin B12 deficiency (P < 0.001). Twelve (63%) of the 19 vitamin B12-deficient patients had elevated total homocysteine levels. In all participants with vitamin B12 deficiency who received treatment (15 of 21), methylmalonic acid and total homocysteine levels decreased substantially, confirming the deficiency before treatment.
  
  
  CONCLUSIONS
  Patients who have had gastric surgery have a high prevalence of vitamin B12 deficiency. Prompt recognition and treatment of the deficiency with resultant normalization of elevated total homocysteine and methylmalonic acid levels may prevent the development of cardiovascular, hematologic, and neurologic abnormalities. Our data support both frequent screening and vitamin B12 replacement therapy in patients who have had gastric surgery and have serum vitamin B12 levels less than 221 pmol/L.
authors.affiliation: Philadelphia Veterans Affairs Medical Center, Pennsylvania, USA.
authors.forename: A E
authors.initials: AE
authors.lastname: Sumner
authors.forename: M M
authors.initials: MM
authors.lastname: Chin
authors.forename: J L
authors.initials: JL
authors.lastname: Abrahm
authors.forename: G T
authors.initials: GT
authors.lastname: Berry
authors.forename: E J
authors.initials: EJ
authors.lastname: Gracely
authors.forename: R H
authors.initials: RH
authors.lastname: Allen
authors.forename: S P
authors.initials: SP
authors.lastname: Stabler
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003430:Cross-Sectional Studies; D005260:Female; D006710:Homocysteine / Q000097:blood*; D006801:Humans; D008297:Male; D008764:Methylmalonic Acid / Q000097:blood*; D008875:Middle Aged; D011183:Postoperative Complications / Q000097:blood*; D013270:Stomach / Q000601:surgery*; D014805:Vitamin B 12 / Q000097:blood; D014806:Vitamin B 12 Deficiency / Q000097:blood / Q000175:diagnosis* / Q000188:drug therapy
chemical_list: D006710:Homocysteine; D008764:Methylmalonic Acid; D014805:Vitamin B 12