The quantitative insulin sensitivity check index QUICKI predicts the onset of type 2 diabetes better than fasting plasma insulin in obese subjects;: a 5-year follow-up study

The aim of the present study was to evaluate the predictive value of QUICKI and fasting plasma insulin (FPI) as predictors of the onset of type 2 diabetes mellitus. We performed a five-year follow-up study in a sample of middle-aged subjects with at least one of the following risk factors; hypertension defined as systolic blood pressure greater than or equal to160 mmHg and/or diastolic blood pressure greater than or equal to90 mmHg or medication for hypertension, obesity defined as a body mass index greater than or equal to30 kg/m(2) and/or a waist-to-hip ratio greater than or equal to 1.00 in men and greater than or equal to 0.88 in women, or a family history of type 2 DM. When the QUICKI index was used to compare the tertile with the lowest risk to the tertile of the highest risk of obese subjects, Odd's Ratio (OR) for type 2 diabetes was 7.77 (95% CI 1.63-37.04). Correspondingly, when the middle tertile was compared to the highest, OR was 5.29 ( 95% CI 1.39-20.24). For FPI, the respective OR's were 2.84 (95% CI 0.82-9.82) and 3.96 (95% CI 1.02-15.48). QUICKI and fasting insulin did not have a statistically significant predictive value among non-obese subjects. Concerning QUICKI, the subjects in the tertiles at the medium and highest risk had a higher risk for type 2 DM than the corresponding tertiles of FPI among obese subjects.