Background: Insulin resistance and hyperinsulinaemia have been reported among patients with chronic renal failure. However, little is known concerning insulin sensitivity among patients with hypertensive kidney disease (HKD), especially in those with moderate or severe renal dysfunction.
Methods: We examined and compared 30 patients with HKD, 30 normotensive patients with chronic kidney disease (CKD-NT), 30 normal controls and 30 patients with hypertension and normal renal function (HTN). Moderate and severe renal dysfunction were defined according to the K/DOQI definitions (estimated glomerular filtration rates between 15 and 59 ml/min per 1.73 m(2)). The homeostasis model assessment of insulin resistance (HOMA-R) and three surrogate indexes based on 75 g oral glucose tolerance test results were used to determine insulin sensitivity.
Results: A trend to higher HOMA-R values in the HTN and HKD groups than in the other groups was noted, but the difference was not statistically significant. The insulin sensitivity index (ISI) proposed by Stumvoll et al. was significantly lower in the HTN, HKD and CKD-NT groups than in controls and was significantly lower in HKD than in the HTN and CKD-NT groups. The insulin sensitivity index proposed by Gutt et al. was significantly lower in HKD than in the control and HTN groups and showed a trend to being lower in HKD than in CKD-NT. The same patterns prevailed in the oral glucose ISI. We assumed that subjects whose ISI values decreased below the mean value minus 2-SD in the control group manifest apparent insulin resistance. According to this criterion, approximately 40% of HKD subjects were in an insulin-resistant state: only <10% of HTN subjects and approximately 10-30% of CKD-NT subjects were insulin resistant.
Conclusions: HKD with moderate to severe renal dysfunction is associated with insulin resistance.