Serum vitamin B12 status of patients with type 2 diabetes mellitus on metformin

Abstract

Background: Metformin use is a known cause of B12 deficiency in patients with type 2 DM (T2DM). Diabetic peripheral neuropathy (DPN) often has clinically indistinguishable clinical features of B12 deficiency-induced peripheral neuropathy (PN). Objective: The present study aims to assess serum vitamin B12 levels in patients with T2DM on metformin. Subjects and Methods: This cross-sectional study was conducted at a specialized endocrine outpatient clinic in Cumilla, Bangladesh, over six months from January 2020 to June 2020. Non-pregnant adults (≥18 years age) receiving metformin for T2DM for at least six months were evaluated for PN and assessed for serum B12 levels. Results: Among 90 subjects evaluated, 28 (31.1%) had B12 deficiency and 6 (6.7%) had borderline B12 deficiency; 56 (62.2%) had normal B12 levels. Study subjects with subnormal B12 used metformin for a longer duration [8.5 (7.0-14.0) vs. 5.0 (2.25-10.0) years, median (IQR), P = 0.006], gram-years of metformin use was higher in them [12.0 (7.9-14.0) vs. 5.75 (2.0-13.6) years, median (IQR), P = 0.005] and they had a higher mean corpuscular volume [85.9±7.2 vs. 82.4±6.4 fL, mean±SD, P = 0.020] compared to those having normal B12 levels. Serum B12 levels had a strong negative correlation with duration of metformin use and gram-years of metformin use. B12 status did not influence the presence and severity of PN. Conclusions: A considerable number of patients with T2DM have subnormal B12 levels. Periodic screening for serum vitamin B12 level may be of clinical benefit in such patients.

Effect of metformin on vitamin B12 and homocysteine levels among Sudanese with type 2 diabetes mellitus

“…The present study found that there was no correlation between serum VitB12 level and the percentage of HbA1c or the age of the participant. These ndings are consistent with several previous studies such as Shahwan et al (2020) [11] , Kim et al (2019) [18] , Alam et al (2021) [30] , Sugawara et al (2020) [32] , and Al Hamdi et al (2020) [31] .…”

“…In the current study, the correlation between serum VitB12 level and metformin dose is insigni cant. This result was also showed by Saber et al (2019) [29] , and Alam et al (2021) [30] , but this nding in contrast to ve previous studies reported by Miyan et al (2020) [7] , Al Hamdi et al (2020) [31] , Kim et al (2019) [18] ,…”

“…This outcome is in agreement with the results of the study by Saber et al (2019) [29] , Al Hamdi et al (2020) [31] , Kim et al (2019) [18] , Hashem et al (2021) [19] and Sugawara et al (2020) [32] . In the contrast to this nding are the results of the study by Miyan et al (2020) [7] and Alam et al (2021) [30] who showed a correlation between VitB12 level and metformin use duration. This insigni cant correlation, may be because the time of this study was very short and the size of the samples was small, and this did not give me much opportunity to study this correlation more broadly.…”

Bipolar Affektif Bozukluk Tanılı Bireylerin B12 Düzeyi Yönünden Değerlendirilmesi: 10 Yıllık Retrospektif Çalışma

“…D vitamininin de B12 vitamini gibi bipolar affektif bozukluk üzerinde etkisi bilinmesine karşın poliklinik ve kliniklerde bu kan değerlerine bakılmaması nedeniyle yaş, cinsiyet, medeni durum, eğitim durumu, vücut kitle indeksi, ailede psikiyatrik hastalık durumu, alkol kullanımı, sigara kullanımı, madde kullanımı, kan hemoglobin düzeyi, son yatış süresi, kullandığı ilaç türü ve EKT alma durumu arasında herhangi bir ilişki durumu değerlendirilememiştir. Oysa doğru tanı ve tedavi için D vitamini de B12 vitamini gibi bakılması gerekli olan bir kan değeridir (31)(32)(33).…”

Comparison of Serum Vitamin B12 Levels Among Drug-Naïve and Metformin-Treated Patients With Polycystic Ovary Syndrome

“…Metformin-associated B12 deficiency in T2DM was first described in 1969, and since then, many researchers have confirmed the dose-dependent lowering of B12 levels with metformin [ 10 , 11 , 19 ]. Only a few studies have evaluated the changes in vitamin B12 in metformin-treated patients with PCOS, and there is great heterogenicity among the study results.…”