Purpose: Chronic sulphonylurea treatment maintains improved glycaemic control through mechanisms other than enhancement of insulin secretion and may act on various organs. The aim of this study was to investigate whether the chronic use of sulphonylurea drugs influences PET measurement of myocardial glucose utilisation (MGU) in type II diabetes mellitus.
Methods: Forty-two patients with type II diabetes mellitus and 17 control subjects underwent dynamic (18)F-FDG PET to measure MGU during hyperinsulinaemic euglycaemic clamping. Twenty-one patients had been taking sulphonylurea drugs for more than 1 year (SU group), and the other 21 patients were drug naive (non-SU group). The haemoglobin A1c levels in the two patient groups were similar. Glucose disposal rate (GDR) was also determined as a marker of whole-body insulin resistance.
Results: GDR in the SU group (9.01+/-2.53 mg min(-1) kg(-1)) was significantly higher than that in the non-SU group (4.10+/-2.47, p<0.01) and was similar to that in the controls (9.76+/-2.97). MGU in the SU group (7.66+/-3.02 mg min(-1) 100 g(-1)) was significantly higher than that in the non-SU group (5.53+/-2.05, p<0.01) and was similar to that in the controls (7.49+/-2.74).
Conclusion: Chronic sulphonylurea treatment influences MGU independent of the degree of glycaemic control. The effect of medication should be kept in mind when measuring and interpreting MGU in patients with type II diabetes mellitus.