Evaluating the Association between Vitamin B12 Deficiency and Peripheral Neuropathy in Patients with Diabetes

Abstract

Objective: The objective of this study is to ascertain if there is an association between vitamin B12 deficiency and peripheral neuropathy in patients with diabetes.Methods: We identified 7,929 patient records from January 2009 to July 2013 with a serum vitamin B12 concentration and a diagnosis of diabetes only (DO) or diabetes and peripheral neuropathy (DPN). Results: Of the 5,709 patients included (4,650 in DO and 1,059 DPN), 447 patients had a documented vitamin B12 concentration ≤ 250 pg/ml (361 in DO and 86 in DPN). Neither the mean vitamin B12 concentration nor incidence of vitamin B12 deficiency was significantly different between the DO and DPN groups (683 pg/ml vs. 693 pg/ml, p=0.77) (361 (7.8%) vs. 86 (8.1%), p=0.70). Those patients who used metformin and those patients age ≥55 were foundto have an increased incidence of vitamin B12 deficiency (96 (12.3%) vs. 351 (7.1%), p<0.0001) (384 (8.2%) vs. 63 (6.0%), p=0.02). Yet, only patients age ≥65 were found to have an increased incidence of neuropathy with vitamin B12 deficiency (242 (8.2%) vs. 70 (11.0%), p=0.02).Conclusions: Metformin and age ≥55 were associated with decreased vitamin B12 concentrations. In addition, vitamin B12 deficiency was not found to be associated with neuropathy in patients with diabetes. However, in a subgroup analysis, vitamin B12 deficiency was associated with an increased likelihood of neuropathy in patients with diabetes age ≥65.