title: Ambulatory care increased vitamin B12 requirement associated with chronic acid suppression therapy.
abstract: BACKGROUND
  Assimilation of vitamin B(12) from dietary sources requires gastric acid. By decreasing acid production, the proton pump inhibitors (PPIs) and histamine(2) (H(2))-blockers may reduce vitamin B(12) absorption.
  
  
  OBJECTIVE
  To determine whether chronic acid suppression therapy is associated with the initiation of vitamin B(12) supplementation, we conducted a retrospective case-control study using a state-wide Medicaid population.
  
  
  METHODS
  Case patients were identified as those who initiated vitamin B(12) supplementation during the study period. Four control patients were age- and gender-matched to each case. Patients (n = 109 844) with a paid claim between September 27, 1995, and September 27, 1997, were eligible for inclusion. Chronic acid suppression therapy was defined as treatment with H(2)-blockers or PPIs for >/=10 of the 12 months prior to the first vitamin B(12) injection. Comparisons were made between the case and control groups regarding exposure to chronic acid suppression therapy.
  
  
  RESULTS
  One hundred twenty-five cases were matched to 500 controls. Twenty-three patients (18.4%) had been exposed to chronic acid suppression therapy compared with 55 (11.0%) of the control group (p = 0.025; OR 1.82; 95% CI 1.08 to 3.09).
  
  
  CONCLUSIONS
  Initiation of vitamin B(12) supplementation was associated with chronic gastric acid suppression therapy.
authors.affiliation: Idaho Drug Utilization Review Program (IDURP), Department of Family Medicine, Idaho State University, Pocatello, ID 83209, USA. force@otc.isu.edu
authors.forename: Rex W
authors.initials: RW
authors.lastname: Force
authors.forename: Angela D
authors.initials: AD
authors.lastname: Meeker
authors.forename: Paul S
authors.initials: PS
authors.lastname: Cady
authors.forename: Vaughn L
authors.initials: VL
authors.lastname: Culbertson
authors.forename: Wendy S
authors.initials: WS
authors.lastname: Force
authors.forename: Craig M
authors.initials: CM
authors.lastname: Kelley
mesh_terms: D000553:Ambulatory Care; D000897:Anti-Ulcer Agents / Q000009:adverse effects*; D016022:Case-Control Studies; D019587:Dietary Supplements; D005260:Female; D005745:Gastric Acidity Determination; D006801:Humans; D008297:Male; D012189:Retrospective Studies; D014805:Vitamin B 12 / Q000008:administration & dosage* / Q000378:metabolism / Q000493:pharmacokinetics* / Q000494:pharmacology
chemical_list: D000897:Anti-Ulcer Agents; D014805:Vitamin B 12