SLR - December 2012 - Salem

Association of Biochemical B12 Deficiency with Metformin Therapy and Vitamin B12 Supplements: the National Health and Nutrition Examination Survey, 1999–2006

Refrence: Reinstatler L, Qi YP, Williamson RS, Garn JV, Oakley Jr GP. Association of biochemical B12 deficiency with metformin therapy and vitamin B12 supplements: the national health and nutrition examination survey, 1999-2006. Diabetes Care. 2012;35:327- 33.

Scientific Literature Review

Reviewed by: Munketh S. Salem, DPM
Residency Program:  KSUCPM and UH Richmond Heights Medical Center

Podiatric Relevance:
Diabetes and diabetic neuropathy, as well as other types of neuropathy, are commonly diagnosed, managed and treated by podiatric physicians in coordination with the patient’s primary care physician.

Methods:
Data analysis was performed on adults over the age of 50 with (n=1,621) or without (n=6,867) type 2 diabetes from the National Health and Nutrition Examination Survey, 1999–2006. Type 2 diabetes was defined as clinical diagnosis after age 30 with no insulin therapy within one year. Patients with diabetes were classified according to their current metformin dose. B12 deficiency was defined as serum B12 concentrations ≤148 pmol/L and borderline deficiency was defined as >148 to ≤221 pmol/L.

Results:
B12 deficiency was found in 5.8 percent of diabetics on metformin, 2.4percent of diabetics not taking Metformin, and 3.3 percent of non-diabetic patients. Taking a daily supplement containing B12 did not reduce the prevalence of B12 deficiency in diabetics, but reduced its prevalence to 67 percent in non-diabetics.

Conclusions:
The use of metformin in diabetic treatment can result in increased risk of B12 deficiency which must be tested for and treated properly. Daily supplements are not sufficient enough to correct B12 deficiency in diabetics. This deficiency can contribute to as well as be the source of diabetic neuropathic symptoms.

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