Physician Measurement of Vitamin B12 Is Not Influenced by Proton Pump Inhibitor Dose

Abstract

Purpose: Proton pump inhibitors (PPIs) are among the most commonly prescribed medications in the U.S. These medications target parietal cell hydrogen potassium ATPase to potently reduce gastric acid. Chronic use of PPIs is speculated to decrease vitamin B12 absorption. This study evaluated the impact of PPI dose upon the rate of physician vitamin B12 measurement. Methods: A retrospective medical record review was performed utilizing a multispecialty electronic health record. Consecutive patients on chronic PPIs during a 6-month period seen in an urban, academic gastroenterology clinic were included. There were no exclusion criteria. Patient age, gender, PPI dose and duration, and vitamin B12 were obtained. Low-dose PPI was considered to be an over-the-counter regimen. High-dose PPI was a prescribed regimen. A database, maintaining patient confidentiality, was created. Statistical analysis was performed using Fisher's exact test with statistical significance set at p<0.05. The study was approved by the university's IRB. Results: Two hundred thirty-four records (88 men, 146 women; mean age 54.9 years) were reviewed. Eighty-nine (38%) patients (28 men, 61 women) had vitamin B12 checked. There was no significant difference (p=0.1644) in the rate at which vitamin B12 was checked based on gender. The average age at which patients with vitamin B12 checked was 59.67 years. Forty-one patients were on a low-dose PPI regimen and 193 patients were on a high-dose PPI regimen. Twenty-two of 41 (53.7%) low-dose PPI users had vitamin B12 measured. Sixty-seven of 193 (34.7%) patients on prescribed PPIs had vitamin B12 measured. There was a statistically significant difference (p=0.0327) in the rate at which low-dose and high-dose chronic PPI users had vitamin B12 measured. There was no significant difference in vitamin B12 level based on PPI dose. The mean vitamin B12 level in those on high-dose PPI was 750 pg/mL (618-883) and low dose PPI was 736 pg/mL (636-836). Conclusion: Vitamin B12 is necessary for neurologic function, blood cell formation, DNA synthesis, and cellular metabolism. Deficiency can result in a variety of disorders, including irreversible damage to the brain and nervous system. It has been speculated that chronic PPI use can result in low vitamin B12 levels and may influence clinicians to evaluate for B12 deficiency. However, this study revealed that vitamin B12 was inconsistently measured in patients on chronic PPIs. Additionally, patients on low-dose PPIs more frequently had vitamin B12 measured than those on high-dose PPIs. Continued attention to the potential relationship of PPIs and vitamin B12 is important to determine if vitamin B12 monitoring is important in chronic PPI users.