Estimates of insulin sensitivity from the intravenous-glucose-modified-clamp test depend on suppression of lipolysis in type 2 diabetes: a randomised controlled trial

Aims/hypothesis The combined IVGTT–hyperinsulinaemic–euglycaemic clamp (Botnia clamp) allows the assessment of insulin secretion and sensitivity in one experiment. It remains unclear whether this clamp yields results comparable with those of the standard hyperinsulinaemic–euglycaemic clamp (SHEC) in diabetes patients. We hypothesised that the IVGTT induces responses affecting insulin sensitivity assessment. Methods Of 22 randomised diet- or metformin-treated patients with well-controlled type 2 diabetes, 19 randomly underwent a Botnia clamp and an SHEC, spaced by 2 weeks, in one clinical research centre in a crossover study. The main outcomes were whole-body and hepatic insulin sensitivity as measured by the clamp and [6,6- 2 H 2 ]glucose. Substrate utilisation was assessed from indirect calorimetry and beta cell function from insulin dynamics during IVGTT. Results The values of whole-body insulin sensitivity obtained from Botnia clamp and SHEC were correlated ( r = 0.87, p