Patient Age and Duration of PPI Therapy Affect Vitamin B12 Measurement in Chronic PPI Users

Abstract

Purpose: Vitamin B12 is necessary for DNA synthesis and neurologic function. Dietary B12 is bound to protein and requires gastric acid to become available for intrinsic factor-mediated absorption. Because proton pump inhibitors (PPIs) increase gastric pH, it has been speculated that there may be a decrease in vitamin B12 absorption with chronic use. This study evaluated the rate of vitamin B12 measurement in patients maintained on chronic PPIs. 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, duration of PPI therapy, and vitamin B12 were obtained. A database, maintaining patient confidentiality, was created. Categorical variables were compared 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 patients (38%) 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 and without vitamin B12 checked was 51.89 years. There was a significant difference (p=0.0196) in the rate of vitamin B12 measurement in patients less than 60 years of age (44/139; 31.7%) and patients greater than 60 years of age (45/95; 47.4%). The mean duration of therapy in which vitamin B12 was measured was 27.85 months and in which vitamin B12 was not measured was 18.37 months. There was a significant difference (p=0.0016) in the rate at which vitamin B12 was measured in patients treated for less than 18 months (36/124; 29%) compared to those treated greater than 18 months (52/104; 50%). There was also a significant difference (p=0.0153) in the rate at which vitamin B12 was measured in patients treated for less than 30 months (55/164; 33.5%) compared to those treated greater than 30 months (33/64; 51.6%). Conclusion: This study revealed that older patients on chronic PPIs were significantly more likely to have vitamin B12 measured. Additionally, patients with a longer duration of PPI use more often had vitamin B12 measured than those with shorter duration of therapy. The cause of these differences is not clear. Older patients may have more frequent medical attention due to comorbidities, prompting increased laboratory testing. It is important that attention be given to the possibility of vitamin B12 deficiency in all patients on chronic PPIs.