The Influence of Sitagliptin on Treatment-Related Quality of Life in Patients with Type 2 Diabetes Mellitus Receiving Insulin Treatment: A Prespecified Sub-Analysis

INTRODUCTION: Treatment-related quality of life (QOL) is an important aspect of diabetes management. Here, we investigated the influence of sitagliptin, a dipeptidyl peptidase-4 inhibitor, on treatment-related QOL in patients with type 2 diabetes mellitus treated with insulin. METHODS: This was a prespecified sub-analysis of the Sitagliptin Preventive Study of Intima-Media Thickness Evaluation (SPIKE). The study population consisted of 71 subjects in the sitagliptin group, and 62 subjects in the conventional group who were treated with insulin. Patients of the sitagliptin group were started on sitagliptin in addition to ongoing insulin therapy. In the conventional group, either increasing the dose of current insulin therapy or the addition of oral hypoglycemic agents other than dipeptidyl peptidase-4 inhibitors was allowed to achieve glycemic control. Treatment-related QOL was evaluated before and 104 weeks after the initiation of the study using the Diabetes Therapy-Related QOL Questionnaire 7 (DTR-QOL7). RESULTS: Forty-five out of 71 subjects in the sitagliptin group and 41 out of 62 subjects in the conventional group filled out the QOL questionnaire at week 104. The DTR-QOL7 score at week 104 was significantly increased from baseline in the sitagliptin group, while that in the conventional group was not changed. However, the changes in score did not differ between the two groups. Change in HbA1c was negatively associated with change in score. CONCLUSIONS: Our data suggest that sitagliptin added to insulin treatment was comparable to other treatments in terms of its impact on treatment-related QOL. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov identifier: UMIN000007396. FUNDING: Mitsubishi Tanabe Pharma Co., Ono Pharmaceutical Co., and Novo Nordisk.