Response: Comparison of the Efficacy of Rosuvastatin Monotherapy 20 mg with Rosuvastatin 5 mg and Ezetimibe 10 mg Combination Therapy on Lipid Parameters in Patients with Type 2 Diabetes Mellitus (Diabetes Metab J 2019;43:582-9).

We deeply appreciate Professor Son's interest and constructive comments on our recently published article “Comparison of the efficacy of rosuvastatin monotherapy 20 mg with rosuvastatin 5 mg and ezetimibe 10 mg combination therapy on lipid parameters in patients with type 2 diabetes mellitus” which was published in Diabetes & Metabolism Journal [1].

As Professor Son pointed out, serum triglyceride levels can be affected by lifestyle factors including diet, exercise, and alcohol consumption [2]; unfortunately, however, we did not fully account for these factors in our analysis, and this might be another limitation of this study. Another issue regarding serum triglyceride levels was that the levels were significantly higher in the rosuvastatin and ezetimibe combination group than rosuvastatin monotherapy group at baseline. To partly overcome this limitation, we compared the percent reduction of serum triglyceride after the treatment. The results showed the reduction in serum triglyceride in both absolute value and percentage were greater in the rosuvastatin and ezetimibe combination group (30.6%) than rosuvastatin monotherapy group (7.2%, P=0.03).

In this study, all participants achieved the goal of low density lipoprotein cholesterol (LDL-C) <100 mg/dL except one subject in the rosuvastatin and ezetimibe combination group (93.8%). However, both regimens in our study were actually high intensity statin (rosuvastatin 20 mg daily) therapy or a therapy using comparable LDL-C reduction efficacy (rosuvastatin 5 mg and ezetimibe 10 mg daily) [3]. Therefore, we further analyzed the achievement of a more stringent goal: serum LDL-C <70 mg/dL. As a result, 80% of rosuvastatin 20 mg monotherapy group and 81% of rosuvastatin 5 mg and ezetimibe 10 mg combination therapy group achieved this goal.

Finally, as we described as a limitation of this study and as Professor Son mentioned, it would be necessary to compare the effects of these two lipid lowering regimens on glucose tolerance and insulin sensitivity with a longer period and more valid methods.

We would like to express our sincere gratitude to Professor Son again for the valuable comments.