Background: In people with type 2 diabetes, a dipeptidyl peptidase-4 (DPP-4) inhibitor is one choice as second-line treatment after metformin, with basal insulin recommended as an alternative. We aimed to compare the efficacy, tolerability, and safety of insulin glargine and sitagliptin, a DPP-4 inhibitor, in patients whose disease was uncontrolled with metformin.
Methods: In this comparative, parallel, randomised, open-label trial, metformin-treated people aged 35-70 years with glycated haemoglobin A(1c) (HbA(1c)) of 7-11%, diagnosis of type 2 diabetes for at least 6 months, and body-mass index of 25-45 kg/m(2) were recruited from 17 countries. Participants were randomly assigned (1:1) to 24-week treatment with insulin glargine (titrated from an initial subcutaneous dose of 0·2 units per kg bodyweight to attain fasting plasma glucose of 4·0-5·5 mmol/L) or sitagliptin (oral dose of 100 mg daily). Randomisation (via a central interactive voice response system) was by random sequence generation and was stratified by centre. Patients and investigators were not masked to treatment assignment. The primary outcome was change in HbA(1c) from baseline to study end. Efficacy analysis included all randomly assigned participants who had received at least one dose of study drug and had at least one on-treatment assessment of any primary or secondary efficacy variable. This trial is registered at ClinicalTrials.gov, NCT00751114.
Findings: 732 people were screened and 515 were randomly assigned to insulin glargine (n=250) or sitagliptin (n=265). At study end, adjusted mean reduction in HbA(1c) was greater for patients on insulin glargine (n=227; -1·72%, SE 0·06) than for those on sitagliptin (n=253; -1·13%, SE 0·06) with a mean difference of -0·59% (95% CI -0·77 to -0·42, p<0·0001). The estimated rate of all symptomatic hypoglycaemic episodes was greater with insulin glargine than with sitagliptin (4·21 [SE 0·54] vs 0·50 [SE 0·09] events per patient-year; p<0·0001). Severe hypoglycaemia occurred in only three (1%) patients on insulin glargine and one (<1%) on sitagliptin. 15 (6%) of patients on insulin glargine versus eight (3%) on sitagliptin had at least one serious treatment-emergent adverse event.
Interpretation: Our results support the option of addition of basal insulin in patients with type 2 diabetes inadequately controlled by metformin. Long-term benefits might be expected from the achievement of optimum glycaemic control early in the course of the disease.
Copyright © 2012 Elsevier Ltd. All rights reserved.