Daytime Glibenclamide and Bedtime NPH Insulin Compared to Intensive Insulin Treatment in Secondary Sulphonylurea Failure: a 1-year Follow-up

The aim of this study was to compare the metabolic effects of a combination of daytime glibenclamide and evening NPH insulin with intensive insulin treatment (rapid acting insulin before meals and NPH insulin at bedtime) in patients exhibiting secondary failure to sulphonylurea treatment. Thirty-nine mildly obese NIDDM patients (BMI 25.6 +/- 0.5) were randomized after 6 weeks of intensive insulin treatment to either a combination treatment (CT, n = 20) or continued intensive insulin treatment (IT, n = 19). There were no differences between the two groups in age, diabetes duration, BMI, HbA1c, or basal and glucagon stimulated C-peptide. The patients were followed for 1 year and the findings were analysed on an intent to treat basis. Two patients in the CT group were excluded after 2 and 6 months, respectively, due to unacceptably high postprandial glucose values. There was a significant difference in HbA1c between the CT and IT groups at 6 months (8.2 +/- 0.2, n = 19, vs 6.8 +/- 0.4%, n = 19, p < 0.001)), but not at 12 months (7.8 +/- 0.3, n = 18, vs 7.5 +/- 0.4%, n = 19). After the initial intensive insulin treatment, BMI was constant in the CT group but increased significantly at 6 and 12 months in the IT group. We conclude that both treatments are associated with a marked and long-term improvement of glycaemic control. The intensive insulin treatment leads to a more pronounced weight increase which in the long run might have negative effect on overall metabolic control. Therefore, the combination treatment together with intensified education and dietary advice should be regarded as the initial treatment of choice for oral agent failure in moderately obese NIDDM patients.