A randomized trial of adding insulin glargine vs. avoidance of insulin in people with Type 2 diabetes on either no oral glucose‐lowering agents or submaximal doses of metformin and/or sulphonylureas. The Canadian INSIGHT (Implementing New Strategies with Insulin Glargine for Hyperglycaemia Treatment) Study

Abstract

Aims Insulin is generally withheld until people with Type 2 diabetes are unresponsive to other therapies. However, its potential advantages suggest that it could be added earlier to achieve glycaemic goals; this possibility was tested in a clinical trial. Methods Consenting adults aged 18–80 years with Type 2 diabetes for at least 6 months, HbA_1c of 7.5–11%, and on 0, 1 or 2 oral agents, were randomized to one of two therapeutic approaches for 24 weeks: evening insulin glargine plus self‐titration by 1 unit/day if the fasting plasma glucose (FPG) was > 5.5 mmol/l; or conventional therapy with physician adjustment of oral glucose‐lowering agents if capillary FPG levels were > 5.5 mmol/l. The primary outcome was the first achievement of two consecutive HbA_1c levels ≤ 6.5%. Results Two hundred and six participants were allocated to glargine and 199 to oral agents. Compared with control subjects, participants receiving glargine: (i) were 1.68 times more likely to achieve two consecutive HbA_1c levels ≤ 6.5% (95% CI 1.00–2.83; P = 0.049); (ii) reduced their HbA_1c by 1.55 vs. 1.25% (P = 0.005), achieving adjusted means of 7.0 vs. 7.2% (P = 0.0007); (iii) had lower FPG (P = 0.0001), non‐high‐density lipoprotein (HDL) cholesterol (P = 0.02) and triglycerides (P = 0.02); (iv) had greater increases in treatment satisfaction (P = 0.045); and (v) had a 1.9‐kg greater increase in weight (P < 0.0001). No differences in hypoglycaemia were noted. Conclusions Adding insulin glargine is more likely to achieve a lower HbA_1c level than conventional therapy with oral agents.