Insulin treatment of patients with type 2 diabetes : Risks and benefits

Abstract: Patients with Type 2 diabetes and secondary failure to oral hypoglycaemic agents were characterized before and during insulin treatment. During oral treatment the 24-h area under the curve for free insulin in blood was similar to that in healthy subjects. However, the insulin profile was abnormal, with normal fasting free insulin but insufficient prandial response. Plasma concentrations of triglyceride-rich lipoproteins were elevated, and the high density lipoprotein (HDL) cholesterol concentration was low.Insulin treatment caused hyperinsulinaemia, with a 2-3-fold increase in 24-h free insulin concentration. The mean blood glucose concentration and HbAlc were almost normalized, and glycaemic control remained improved even after 2-3 years of insulin treatment. A multi-injection regimen, based on preprandial regular insulin and intermediate-acting insulin at bedtime, gave slightly better prandial glycaemic control than a regimen based on twice-daily injections of mainly intermediate-acting insulin, but the overall glycaemic control was similar in both. Insulin treatment reduced the elevated proinsulin concentration that is present in Type 2 diabetes and also lowered the endogenous insulin secretion. The percentage change in blood C-peptide concentration was closely correlated with the percentage change in blood glucose concentration, but not with the percentage change in free insulin concentration. The lipid profile was improved, with marked reduction in the triglyceride-rich lipoprotein concentration and a small increase in HDL cholesterol. Microalbuminuria was reduced and there was no increase in PAI-l antigen concentration. Weight gain occurred during the first year of insulin treatment but not subsequently. Blood pressure was unchanged after 2-3 years of insulin treatment. Severe hypoglycaemic episodes were rare but such can cause cardiac arrhythmia. Patients reported that they felt better.Insulin treatment of patients with Type 2 diabetes and secondary failure to oral hypoglycaemic agents improves glycaemic control and improves or has no adverse effect on the major cardiovascular risk factors.