Relationship Between Duration of Type 2 Diabetes and Effectiveness of DPP-4 Inhibitor Versus Sulfonylurea as Add-on Therapy: A Post Hoc Analysis

INTRODUCTION: To assess the impact of duration of type 2 diabetes on glucose-lowering effectiveness of the dipeptidyl peptidase-4 (DPP-4) inhibitor vildagliptin versus sulfonylureas (SUs) in a real-life setting. METHODS: Data were extracted from the large 1-year, observational EDGE study (N = 45,868). Patients receiving either DPP-4 inhibitor or any SU as add-on to monotherapy were selected (N = 36,164). Impact of the disease duration on change in glycated hemoglobin (HbA1c) levels was evaluated by using a linear multiple regression model. Descriptive statistics assessed the proportion of patients achieving the composite endpoint (HbA1c <7.0%; 53.0 mmol/mol without hypoglycemia or weight gain), stratified by diabetes duration. RESULTS: At baseline, the overall mean (±SD) type 2 diabetes duration was 5.4 ± 5.24 years, and HbA1c was 8.2 ± 1.33% (66.0 ± 14.5 mmol/mol). HbA1c lowering was directly proportional to the baseline HbA1c (−0.69 per unit; 95% CI −0.696, −0.681; p < 0.0001) and inversely proportional to the disease duration (0.01 per year; 95% CI 0.01, 0.013). There was an increased loss of β-cell function (less pronounced HbA1c drop with increasing disease duration) in patients treated with SU-based regimens (0.025; 95% CI 0.022, 0.027) compared with vildagliptin-based regimens (0.005; 95% CI 0.003, 0.007), with the mean adjusted difference being 0.10 (95% CI −0.122, −0.092; p < 0.0001). Consistently, a higher proportion of patients achieved the composite endpoint with vildagliptin over the diabetes duration (less than 2 to more than 10 years). CONCLUSION: Vildagliptin demonstrated less dependency on the duration of type 2 diabetes, whereas the effectiveness of SUs diminished faster with increasing duration of the disease in a real-life setting. FUNDING: Novartis Pharma AG.