Factors affecting the efficacy of starting insulin treatment in Type 2 diabetic patients. A retrospective evaluation

To assess the efficacy and practices of insulin treatment in Type 2 diabetes mellitus in primary health care.

Primary health care in southwest Finland (population 250,000).

Cases in the target area with insulin treatment initiated in 1991-1997 were identified and the patient records were analysed retrospectively for up to 5 years from treatment.

A total of 883 patients with Type 2 diabetes (aged 40-91 years) were identified.

HbA1c and body weight.

HbA1c declined by 2.0 percentage points from 10.0% to 8.0% (p < 0.001) at 12 months from the initiation of insulin, irrespective of age. The decrease was smaller in obese patients (BMI > 34 kg/m2). A slightly better glycaemic control was achieved when the treatment was initiated by a specialist rather than by a general practitioner. The improvement in HbA1c was essentially unchanged at 4 years. The decrease in HbA1c was largely independent of the type of the insulin regimen (insulin alone, combined insulin and oral therapy). The daily insulin dose increased markedly and the proportion of patients on combination therapy decreased from 57% to 38% at 4 years. The mean body weight of the patients increased (3.7 kg at 12 months, 5.7 kg at 4 years). The weight increase was highest in patients treated with insulin alone.

Introducing insulin therapy in poorly controlled Type 2 diabetic patients results in a marked decrease in HbA1c. Insulin therapy can be initiated in all age groups with equal results. Insulin treatment can be initiated and improved metabolic control maintained in primary health care.