Starting insulin in type 2 diabetes: continue oral hypoglycemic agents? A randomized trial in primary care

Abstract

Objective: To evaluate the effects of insulin 30/70 twice daily or bedtime isophane (NPH) insulin plus continued sulfonylurea and metformin in patients with type 2 diabetes in primary care.

Study design: Open-label, randomized trial.

Population: Persons younger than 76 years with type 2 diabetes whose disease had not been controlled with oral hypoglycemic agents alone. A total of 64 insulin-naive patients treated with maximal feasible dosages of sulfonylurea and metformin (baseline glycosylated hemoglobin [HbA1c]=8.5%) were randomly assigned to insulin monotherapy (IM group; n=31) or insulin in addition to unchanged oral hypoglycemic medication (IC group; n=33) for 12 months. Insulin doses were adjusted to obtain fasting glucose <7.0 mmol/L and postprandial glucose <10.0 mmol/L.

Outcomes measured: Outcome measures included HbA1c, treatment failure, weight, hypoglycemic events and symptoms, satisfaction with treatment, general well-being, and fear of injecting insulin and testing.

Results: HbA1c improved from 8.3% to 7.6% in the IC group, and from 8.8% to 7.6% in the IM group (P=NS). The IC group had 24% treatment failures, compared with 2% in the IM group (P=.09). Patients in the IC group had less weight gain than those in the IM group (1.3 vs 4.2 kg; P=.01), and they reported fewer hypoglycemic events (2.7 vs 4.3; P=.02). Increased satisfaction with treatment was equal in the 2 groups, and general well-being improved by 3.0 points more in the IC group (P=.05). Fear of self-injecting and self-testing did not differ.

Conclusions: Bedtime NPH insulin added to maximal therapy with sulfonylurea and metformin is an effective, simple, well-tolerated approach for patients with uncontrolled type 2 diabetes.