Morning or bed-time insulin with or without glibenclamide in elderly type 2 diabetic patients unresponsive to oral antidiabetic agents

Abstract

We studied in a group of elderly (mean age 77 yr) non-obese Type 2 diabetic patients (n = 9) in a randomised, placebo-controlled prospective cross-over study of 8 months duration, the effects of substituting maximal sulfonylurea medication with a single injection of human zinc insulin taken either at bedtime (BTI) or morning (MI). All patients were poorly controlled with oral antidiabetic agents. After a 2-month regimen with either BTI or MI, a glibenclamide (GL, 3.5 mg/day) was given for an additional 2 months. Both insulin regimens decreased mean diurnal blood glucose and glycosylated HbA1c values to a similar extent (2.6-2.7%; p < 0.01-0.05), but with a lower daily insulin dose with BTI (0.30 +/- 0.03 IU/kg) as compared with MI (0.39 +/- 0.05 IU/kg; p < 0.01). A further improvement in metabolic control was observed in both groups after the introduction of GL; the mean reduction in glycosylated HbA1c was 1.4% for BTI and 0.7% for MI (p < 0.01 and 0.05, respectively), In conclusion, a subgroup of poorly controlled elderly Type 2 diabetic patients showed an improvement in metabolic control after a single injection of insulin despite discontinuation of maximal doses of oral antidiabetic agents. After 2 months of insulin treatment, a further improvement was achieved by a low dose of sulfonylurea in these patients who were formerly considered unresponsive to oral antidiabetic agents.