 |
 |

Risk Factors of Vitamin B12 Deficiency in Patients Receiving Metformin
Rose Zhao-Wei Ting, MBBS;
Cheuk Chun Szeto, MD, FRCP;
Michael Ho-Ming Chan, FRCPA, FHKCPath;
Kwok Kuen Ma, MBBS;
Kai Ming Chow, MRCP
Arch Intern Med. 2006;166:1975-1979.
Background Identification of risk factors for metformin-related vitamin B12 deficiency has major potential implications regarding the management of diabetes mellitus.
Methods We conducted a nested case-control study from a database in which the source population consisted of subjects who had levels of both serum vitamin B12 and hemoglobin A1c checked in a central laboratory. We identified 155 cases of diabetes mellitus and vitamin B12 deficiency secondary to metformin treatment. Another 310 controls were selected from the cohort who did not have vitamin B12 deficiency while taking metformin.
Results A total of 155 patients with metformin-related vitamin B12 deficiency (mean ± SD serum vitamin B12 concentration, 148.6 ± 40.4 pg/mL [110 ± 30 pmol/L]) were compared with 310 matched controls (466.1 ± 330.4 pg/mL [344 ± 244 pmol/L]). After adjusting for confounders, we found clinically important and statistically significant association of vitamin B12 deficiency with dose and duration of metformin use. Each 1-g/d metformin dose increment conferred an odds ratio of 2.88 (95% confidence interval, 2.15-3.87) for developing vitamin B12 deficiency (P<.001). Among those using metformin for 3 years or more, the adjusted odds ratio was 2.39 (95% confidence interval, 1.46-3.91) (P = .001) compared with those receiving metformin for less than 3 years. After exclusion of 113 subjects with borderline vitamin B12 concentration, dose of metformin remained the strongest independent predictor of vitamin B12 deficiency.
Conclusions Our results indicate an increased risk of vitamin B12 deficiency associated with current dose and duration of metformin use despite adjustment for many potential confounders. The risk factors identified have implications for planning screening or prevention strategies in metformin-treated patients.
Author Affiliations: Departments of Medicine and Therapeutics (Drs Ting, Szeto, and Chow) and Chemical Pathology (Dr Chan), Prince of Wales Hospital, The Chinese University of Hong Kong, Sha Tin; and Department of Surgery, Queen Mary Hospital (Dr Ma), Hong Kong, China.
CiteULike Connotea Del.icio.us Digg Reddit Technorati Twitter
What's this?
RELATED LETTERS
The Long and Short of Metformin-Related Vitamin B12 Deficiency
George I. Varughese, Abd A. Tahrani, and John H. B. Scarpello
Arch Intern Med. 2007;167(7):729-730.
EXTRACT
| FULL TEXT
Metformin and Vitamin B12 Deficiency: Association and Not Causation May Play a Major Role in Cohort Studies
Ishay Lev
Arch Intern Med. 2007;167(7):730.
EXTRACT
| FULL TEXT
THIS ARTICLE HAS BEEN CITED BY OTHER ARTICLES
 |
Metformin: an old medication of new fashion: evolving new molecular mechanisms and clinical implications in polycystic ovary syndrome
Diamanti-Kandarakis et al.
Eur J Endocrinol 2010;162:193-212.
ABSTRACT
| FULL TEXT
Metformin Extended Release Treatment of Adolescent Obesity: A 48-Week Randomized, Double-Blind, Placebo-Controlled Trial With 48-Week Follow-up
Glaser Pediatric Research Network Obesity Study Gr
Arch Pediatr Adolesc Med 2010;164:116-123.
ABSTRACT
| FULL TEXT
Metformin, B12, and Enhanced Breast Cancer Response to Chemotherapy
Garcia and Tisman
JCO 2010;28:e19-e19.
FULL TEXT
Reply to A. Garcia et al
Jiralerspong and Gonzalez-Angulo
JCO 2010;28:e20-e20.
FULL TEXT
Association of Metformin, Elevated Homocysteine, and Methylmalonic Acid Levels and Clinically Worsened Diabetic Peripheral Neuropathy
Wile and Toth
Diabetes Care 2010;33:156-161.
ABSTRACT
| FULL TEXT
The Prevalence of Vitamin B12 Deficiency in Patients with Type 2 Diabetes: A Cross-Sectional Study
Pflipsen et al.
J Am Board Fam Med 2009;22:528-534.
ABSTRACT
| FULL TEXT
Longitudinal study of Chinese patients with pernicious anaemia
Chan et al.
Postgrad. Med. J. 2008;84:644-650.
ABSTRACT
| FULL TEXT
Metformin for the Treatment of the Polycystic Ovary Syndrome
Nestler
NEJM 2008;358:47-54.
FULL TEXT
Vitamin B12 Deficiency in Patients Receiving Metformin: Clinical Data
Andres and Federici
Arch Intern Med 2007;167:729-729.
FULL TEXT
Metformin and Vitamin B12 Deficiency: Association and Not Causation May Play a Major Role in Cohort Studies
Lev
Arch Intern Med 2007;167:730-730.
FULL TEXT
The Long and Short of Metformin-Related Vitamin B12 Deficiency
Varughese et al.
Arch Intern Med 2007;167:729-730.
FULL TEXT
Metformin-Induced Vitamin B12 Deficiency
JWatch Neurology 2007;2007:3-3.
FULL TEXT
Endocrinology & Metabolism News November 2006
J. Clin. Endocrinol. Metab. 2006;91:17a-17a.
FULL TEXT
|