Metformin and Metformin/Gliptin Combo Therapy tied to lower Vitamin B12 and Ferritin Levels

In a groundbreaking one-year study, researchers have explored the repercussions of metformin and metformin/gliptin combination therapy on the serum concentrations of vitamin B12, ferritin, and folic acid in individuals diagnosed with type 2 diabetes. The findings shed light on potential side effects and the need for vigilant monitoring of these essential nutrients. They found that at 12 months, both metformin and metformin/gliptin groups had low serum ferritin and vitamin B12.

The study results were published in the journal Revista da Association Medica Brasileira. 

Metformin is often the initial choice for monotherapy in managing hyperglycemia, provided no contraindications exist. However, metformin usage may hinder the absorption of vitamin B12 in about 30% of patients. Gliptins, including vildagliptin, saxagliptin, sitagliptin, linagliptin, and alogliptin, are DPP-4 inhibitors that enhance endogenous incretins' effects, resulting in low hypoglycemia risk and modest weight loss, making them well-tolerated options. As previous studies indicated that metformin and metformin/gliptin combination, have effects on vitamin B12, ferritin, and folic acid levels, researchers conducted a study to explore the impact of metformin and metformin/gliptin combination therapy on the serum concentrations of vitamin B12, ferritin, and folic acid in individuals diagnosed with type 2 diabetes.

The study enrolled 118 patients, categorizing them into two groups where 59 patients were prescribed metformin alone, and the remaining 59 patients received a combination of metformin and a gliptin medication. Within the combination therapy group, 35 patients were taking vildagliptin/metformin, while 24 were on sitagliptin/metformin. Researchers meticulously recorded demographic data, including age and gender, and closely examined the patients' initial and 1-year follow-up blood parameters.

Findings:

• One of the most significant findings was related to folic acid.
• In the metformin group, there was a significant decrease in folic acid levels. 
• In contrast, patients on the metformin/gliptin combination therapy did not exhibit the same folic acid decline. 
• Vitamin B12 and ferritin levels saw considerable reductions in both groups.
• Notably, the study did not identify any statistically significant difference in the decrease of vitamin B12 and ferritin between the two groups.
• Therefore, these outcomes underscore the need for constant vigilance and proactive management of vitamin B12 and ferritin levels in individuals with type 2 diabetes under these medications.
• In addition to the nutrient changes, the study unveiled another essential facet of diabetes management. The metformin/gliptin combination therapy group showed a more pronounced decrease in fasting plasma glucose compared to the metformin monotherapy group. 

Thus the study concluded that both metformin and metformin/gliptin combination therapy can lead to low serum ferritin and vitamin B12 levels after one year of treatment. This underscores the importance of proactive monitoring, regular assessments, and personalized care plans for individuals with type 2 diabetes. Patients who are prescribed metformin or metformin/gliptin combination therapy should be vigilant about tracking their vitamin B12 and ferritin levels. Regular check-ups and timely interventions can help manage these potential side effects and ensure the overall health and well-being of individuals with type 2 diabetes.

Further reading: Genc FT, Nalbant A, Genc AC, Kaya T. Effect of a combination of gliptin and metformin on serum vitamin B12, folic acid, and ferritin levels. Rev Assoc Med Bras (1992). 2023;69(11):e20230641. Published 2023 Oct 27. doi:10.1590/1806-9282.20230641