Reply.

We defined diabetes mellitus (DM) as the recent use of antidiabetic drugs, fasting blood glucose >126 mg/dL, and/or hemoglobin A1c >6.5% because 2-h plasma glucose level was a more difficult and time-consuming test to perform than evaluating HbA1c level and fasting plasma glucose. Thus, DM was defined as FPG ≥126 mg/dL, previous diagnosis of diabetes made by a medical doctor, current use of antidiabetic medications, and/or HbA1c ≥6.5%.1) We described that chronic kidney disease (CKD) was defined as having an estimated glomerular filtration rate (eGFR) less than 30 mL/min/1.73 m. In this study, we presented that a person having eGFR less than 30 mL/min/1.73 m was in the stage of near renal failure (Stages 4 and 5 CKD). Moreover, the prevalence of Stage 4 CKD (GFR: 30–15 mL/min/1.73 m2) was also higher in the Japanese general population than in populations of US (for Japan: 0.20% in 2000–20042); for the US: 0.13% in 1999–20003)). One of the post operative major complications in our study was endothermal heat-induced thrombosis (EHIT); however, to classify the injuries, we used only the Kabnick classification. Previously, the American Venous Forum (AVF) reported combining the Kabnick and Lawrence classification into AVF EHIT classification to properly manage and treat EHIT. So, we reported this study in the same way. The purpose of this study was the effectiveness of endovenous radiofrequency ablation (RFA) for older people. Varicose veins in the lower extremities can affect great and small saphenous veins; however, we did not elaborate that in this study because we clarified our purpose. With growing age, healing becomes a slower process. However, we believe that RFA is a minimally invasive therapy. Therefore, healing might not be affected by age. We appreciate these aspects that you pointed out in our study to improve its quality and applicability. We will investigate the further study based on these indications. Further, we hope that you will report more detailed study for RFA.