QUICKI is a useful index of insulin sensitivity in subjects with hypertension

Abstract

Insulin resistance may link disorders of metabolic homeostasis such as diabetes and obesity with disorders of hemodynamic homeostasis such as hypertension. Thus it is of interest to validate simple methods for quantifying insulin sensitivity in hypertensive patients. The quantitative insulin-sensitivity check index (QUICKI) is a novel mathematical transformation of fasting blood glucose and insulin levels. In obese and diabetic subjects, QUICKI has a significantly better linear correlation with glucose clamp determinations of insulin sensitivity than minimal-model estimates. To determine whether QUICKI is also useful in hypertensive subjects, we performed glucose clamps and frequently sampled intravenous glucose tolerance tests (FSIVGTT) on 27 hypertensive subjects taken off antihypertensive medication. Indexes of insulin sensitivity derived from glucose clamp studies (SI Clamp ) were compared with QUICKI, minimal-model analysis of FSIVGTTs (SI MM ), and homeostasis model assessment (HOMA). The correlation between QUICKI and SI Clamp ( r = 0.84) was significantly better than that between SI MM and SI Clamp ( r = 0.65; P < 0.028). The correlation between QUICKI and SI Clamp was comparable to that between 1/HOMA and SI Clamp ( r = 0.82). When studies were repeated in 14 subjects who had resumed antihypertensive medications, the percent changes in SI Clamp for each of these patients were significantly correlated with percent changes in QUICKI ( r = 0.61) and HOMA ( r = −0.54) but not SI MM ( r = −0.18). We conclude that QUICKI is a simple, robust index of insulin sensitivity that is useful for evaluating and following the insulin resistance of hypertensive subjects in both research studies and clinical practice.