Insulin sensitivity in patients with arterial insufficiency. Re-evaluation with the multilevel glucose clamp...

Previous studies have claimed that changes in insulin and glucose metabolism in patients with peripheral arterial insufficiency indicate an increased sensitivity to insulin for glucose uptake. We have re-evaluated this concept in 11 patients with intermittent claudication and 11 matched controls with a multilevel euglycaemic glucose clamp technique. The groups were matched for age, sex and body composition but not completely for smoking habits and physical fitness. Although the control group had a normal physical fitness the patients had 40% lower maximal exercising capacity. The patients' maximal walking capacity was 186 +/- 27 m evaluated on a treadmill. No patient with ischaemic ulcers or rest pain were included. The euglycaemic glucose clamp was performed at five insulin plateau levels (70, 110, 190, 590 and 1440 mU/l) of one h duration each and whole body glucose uptake during the last 20 min was calculated. No differences in maximal glucose uptake (Vmax) or insulin level for half maximal glucose uptake (Km) between the groups were observed. The concentration or the magnitude of the decrease in arterial FFA levels did not differ significantly between the groups at any physiological insulin level. This study can not confirm previously described changes in insulin sensitivity in patients with arterial insufficiency. Although the discrepancy between present and previous results remains unclear it may reflect the combined effects of different methods used, including the selection of reference patients, rather than an increased insulin sensitivity in patients with arterial insufficiency. This study suggests that previous conclusions based on glucose tolerance tests should be interpreted with caution.