Insulin therapy in patients with poorly controlled non-insulin dependent diabetes mellitus

In spite of maximal doses of sulphonylurea agents, patients with poorly controlled non-insulin dependent diabetes (NIDDM) often do not have improved metabolic control after the introduction of insulin therapy. We have assessed 22 patients with NIDDM who commenced insulin therapy in order to identify those characteristics which were associated with an improvement in glycaemic control. Twelve months after the commencement of insulin therapy, 14 (64%) patients showed a decrease in glycosylated haemoglobin (HbA1) levels; 12 of the 14 (55%) patients had achieved HbA1 levels that were considered to reflect acceptable glycaemic control (HbA1 less than or equal to 11%; reference range, 6%-9%). The HbA1 levels in the other patients either remained unchanged or had increased (one subject). When the subjects who had achieved good glycaemic control with insulin therapy were compared with the remainder of the group, a failure to improve with insulin therapy was associated with a longer duration of diabetes, greater obesity and higher levels of cholesterol and triglycerides before the commencement of insulin therapy. Greater obesity and high levels of circulating lipids were found by means of multiple linear regression analysis to correlate independently with a poor response to insulin therapy. We conclude that standard insulin therapy can improve the majority of patients with poorly controlled NIDDM. However, there is a substantial number of patients, who tend to be obese and have high levels of circulating lipids, whose condition does not improve with insulin therapy, or who require more aggressive dosage increases than are used as a routine.