Analysis of the effect of seasonal administration on the efficacy of sitagliptin: Subanalysis of the Januvia Multicenter Prospective Trial in Type 2 Diabetes Study

Abstract

Aims/IntroductionHemoglobin A1c (HbA1c) levels in patients with type 2 diabetes mellitus fluctuate throughout the year. However, there are few studies that have evaluated the therapeutic effect of hypoglycemic agents while considering such fluctuations. In a multicenter study (Januvia Multicenter Prospective Trial in Type 2 Diabetes Study), pretreatment patients with type 2 diabetes mellitus were divided into seven groups and given sitagliptin for 1 year. The aim of the present study was to evaluate the differences in the therapeutic effect, and the efficacy of sitagliptin in patients with type 2 diabetes mellitus based on the month the administration of the drug began as a subanalysis of the Januvia Multicenter Prospective Trial in Type 2 Diabetes Study.Materials and MethodsPatients with type 2 diabetes mellitus were divided into four groups according to the month of initiation of sitagliptin. Changes in HbA1c in each group were compared at 3 and 12 months after administration of sitagliptin. As a negative correlation has been reported between baseline HbA1c and the degree of change after administration of sitagliptin, an analysis using the residual error from the approximate line was carried out.ResultsIn the analysis of the degree of change in HbA1c, patients in the group in which administration of sitagliptin was started between August and October had the lowest degree of improvement at 3 months after starting sitagliptin. However, there was no significant intergroup difference in improvement at 12 months after the start of sitagliptin. The same result was also obtained in residual analysis.ConclusionsThe present study suggested that the season of administration of sitagliptin influenced the subsequent hypoglycemic effect even after analysis excluding the influence of HbA1c value at the start of treatment. This study provides possibility, showing that seasonal fluctuations have an effect on the efficacy of antidiabetic drugs.

Study on the effects of changes in lifestyle of patients with diabetes on glycaemic control before and after the declaration of the state of emergency in Japan

“…There is a report that blood glucose levels fluctuate with the season and HbA1c levels are high in the winter and low in the summer [33][34][35][36][37]. The same has been described in reports on drug effectiveness [38,39]. It is still possible that the season from April to July has an effect.…”

A Study of Seasonal Variation in the Effect of Add-On Sitagliptin on Blood Glucose Control in Insulin-Treated Patients With Type 2 Diabetes

“…Sakura et al have reported on seasonal variation in the effect of sitagliptin in patients who were not using insulin concomitantly [7]. The present study followed their scheme for grouping patients.…”

“…HbA1c was most frequently reported to reach its highest level in March in Japan [1,2,4] and its lowest level in August to October [1][2][3][4]. Therefore, patients were divided into four groups based on the period in which sitagliptin was started: group 1 (in February to April), group 2 (in May to July), group 3 (in August to October), and group 4 (in November to January of the following year), which is the same as previously described [7]. Then changes in HbA1c and BMI at 1, 3, 6, 9, and 12 months from baseline, which was the first day of sitagliptin administration, were compared within each group and among the groups.…”

“…Seasonal variation in hemoglobin A1c (HbA1c) level in pa-tients with type 2 diabetes (T2DM) has been reported [1][2][3][4][5][6][7][8][9]. The most frequently reported month in which HbA1c reached its highest level was March in Japan [1,2,4] and January to March in other countries in the Northern Hemisphere [1][2][3][4][5][6].…”

“…Seasonal variation can interfere with blood glucose control in diabetic patients. However, a report by Sakura et al is the only study that verified seasonal variation in the effect of antidiabetic drugs throughout the year [7], and there has been no study that verified seasonal variation in the effect of antidiabetic drugs used concomitantly with insulin.…”