Ambulatory care increased vitamin B12 requirement associated with chronic acid suppression therapy.
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.
Force
Rex W
RW
Idaho Drug Utilization Review Program (IDURP), Department of Family Medicine, Idaho State University, Pocatello, ID 83209, USA. force@otc.isu.edu
Meeker
Angela D
AD
Cady
Paul S
PS
Culbertson
Vaughn L
VL
Force
Wendy S
WS
Kelley
Craig M
CM
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
D000897:Anti-Ulcer Agents; D014805:Vitamin B 12