Abstract
INTRODUCTION: There have been no studies directly comparing the effect of dipeptidyl peptidase-4 inhibitors with that of metformin on treatment-related quality of life (QOL) when used as first-line therapy in patients with type 2 diabetes mellitus (T2DM). METHODS: This study is a prospective, randomized, open-label, multicenter, parallel-group, comparative study. Forty-four participants who failed to achieve target glycemic control with diet and exercise therapy were randomly allocated to receive linagliptin or metformin therapy. We compared treatment-related QOL among the two groups using the Oral Hypoglycemic Agent Questionnaire, version 2 (OHA-Q version 2) and the self-administered Diabetes Therapy-Related QOL (DTR-QOL) questionnaire. RESULTS: After randomization, 21 patients in the linagliptin group and 22 patients in the metformin treatment group were included in the full analysis set. Biochemical parameters, incidence of adverse effects, and rate of adherence to medication were comparable between the two groups. Over the 24-week treatment period, no significant differences in overall OHA-Q scores between the groups were observed, although the subscale 1 (treatment convenience) score was significantly higher in the linagliptin group than in the metformin group. The overall DTR-QOL score did not differ between the two groups; however, the DTR-QOL scores significantly improved after 24 weeks of linagliptin treatment, but not after metformin treatment. CONCLUSION: We did not find significantly better treatment-related QOL with linagliptin among Japanese patients with T2DM. In terms of treatment convenience, our data showed that linagliptin was superior to metformin. FUNDING: This study was financially supported by Nippon Boehringer Ingelheim Co., Ltd. and Eli Lilly and Company. The journal's article processing fees were covered by a research fund from Juntendo University. CLINICAL TRIAL REGISTRATION: UMIN000022953.