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Ethnicity Plays A Role In Diabetes Drug Selection

Nov 17, 2018
Editor: Steve Freed, R.PH., CDE

Author: Angela Reyes, Pharm.D. Candidate, LECOM College of Pharmacy

The best medication therapy for an individual with type 2 diabetes can depend on many factors, including ethnicity and multiple drug options.

The following is just one example of how drugs can work differently for different ethnic populations. For this study, they used a high dose of metformin with a DPP-4 inhibitor on different ethnic populations. Standard treatment for type 2 diabetes includes medication, diet, weight reduction, and exercise. The first-line medication for type 2 diabetes is metformin, but newer medications are being prescribed with metformin to achieve tighter glycemic control. Dipeptidyl peptidase 4 (DPP-4) inhibitors are a newer antidiabetic medication that have been shown to enhance metformin and lower blood glucose levels even more than monotherapy. DPP-4 medications work by inhibiting DPP-4, an enzyme expressed on the surface of many cells, which deactivates glucose-dependent insulinotropic polypeptides (GIP) and glucagon-like peptide-1 (GLP-1).  A meta-analysis just published examined efficacy and safety of metformin in combination with a DPP-4 inhibitor among different ethnic backgrounds.


As medication therapies become more tailored to an individual based on either gender, ethnicity, or age, new questions about efficacy arise from older medications like metformin. Some studies have shown differences in the effect of metformin on an individual depending on their ethnicity. A 2015 meta-analysis showed the lack of minority subjects involved in research studies on antidiabetes medications yet there is a large number of minorities who have diabetes. The following study gathered articles that compared metformin’s glucose-lowering ability on Caucasian and Asian populations.

A total of 11 studies met criteria for this meta-analysis and were all double-blind and randomized. It grouped subjects in three categories: high-dose metformin therapy, low-dose metformin therapy, or combination of metformin with a DPP-4 inhibitor. Results showed that high-dose combination metformin therapy decreased HbA1c the most (-0.32%, P<0.05) compared to low-dose combination metformin therapy. Initial combinations of a DPP-4 inhibitor and high-dose metformin had significant decrease in HbA1c, fasting plasma glucose (-0.63, P<0.05) and postprandial glucose levels (-0.99, P<0.05). This treatment also produced less increase in body weight than low-dose metformin combination therapy.

When comparing the two ethnic groups examined, the high-dose combination therapy had significant HbA1c (-0.24%, P<0.05) decrease in the Caucasian population than in the Asian population. Fasting glucose (-0.54 mmol/L, P < 0.05) and postprandial glucose levels (-0.94 mmol/L, P < 0.05) were also lower in the Caucasian population. Weight gain was more evident in the Asian population taking high-dose metformin combination therapy.

The findings of these studies show there is a benefit to high-dose metformin in combination with a DPP-4 inhibitor in the treatment of patients with type 2 diabetes. In Asian patients, this combination therapy was effective but not as beneficial compared to Caucasians. These findings help play a role in choosing individualized therapy for a patient with type 2 diabetes.

Practice Pearls:

  • High-dose metformin in combination with a DPP-4 inhibitor is efficacious in the treatment of patients with type 2 diabetes.
  • Combination therapy with a DPP-4 inhibitor and high-dose metformin had better HbA1c lowering and less weight gain than with low-dose metformin combination therapy in the Caucasian population. The Asian population also had similar effects except more weight gain was observed.
  • These findings can help customize a treatment plan for people with type 2 diabetes.


X Cai, X Gao, W Yang, L Ji. Disparities in the Efficacy of Metformin in Combination With Dipeptidyl Peptidase-4 Inhibitor as Initial Treatment Stratified by Dosage and Ethnicity: A Meta-Analysis. Diabetes Technology & Therapeutics(2018);20(10)704-714

Ferdinand KC, Nasser SA. Racial/ethnic disparities in prevalence and care of patients with type 2 diabetes mellitus. Curr Med Res Opin (2015);31:913–923

Angela Reyes, Pharm.D. Candidate, LECOM College of Pharmacy