Objective: To find the response of various regimen of combination therapy (Insulin and Glibenclamide) in type 2 diabetes mellitus subjects who failed to respond to maximum doses of glibenclamide (GBC) plus phenformin.
Methods: A total of 188 subjects with secondary sulfonylurea failure who failed to respond to maximum doses of GBC and phenformin were randomised to receive one of the four regimens. Group A (50 patients) received two doses of insulin; Group B (49 patients) received two doses of insulin and GBC 20 mg/day; Group C (43 patients) received morning dose of insulin with GBC 20 mg/day; and Group D (46 patients) received evening dose of insulin with GBC 20 mg/day. Insulin dose was adjusted to achieve an acceptable blood glucose control. Control of diabetes was revaluated at three months post-treatment period.
Results: Age, duration of diabetes, weight, body mass index (BMI) and biochemical parameters were comparable in all four groups at admission. Dose of insulin was 0.83 +/- 0.07, 0.86 +/- 0.06, 0.46 +/- 0.04 and 0.39 +/- 0.03 units/Kg/day in groups A, B, C and D, respectively. Comparing groups A and B, we found that the dose of insulin (IU/kg/day) required to achieve acceptable fasting blood glucose (FBG) did not differ significantly. Similarly, comparison between Groups C and D did not reveal any significant difference in insulin dose. Mean hospital stay required to achieve an acceptable FBG was 8.42 +/- 0.34, 11.95 +/- 1.11, 8.59 +/- 0.61 and 7.10 +/- 0.48 days in groups A, B, C and D, respectively (p = 0.013). On comparing the four treatment regimens, at three months follow-up, there was a significant increase in bodyweight in Group C; also there was an increase in fasting blood glucose in all the groups except in Group D.
Conclusions: Continuation of GBC in type 2 diabetes mellitus subjects who fail to respond to maximum doses of GBC plus phenformin and who need two doses of insulin for control has no added advantage over giving insulin alone. In subjects controlled on a single dose of insulin with glibenclamide it is preferable to give an evening dose rather than a morning dose.