Cutoff Values of Surrogate Measures of Insulin Resistance for Metabolic Syndrome in Korean Non-diabetic Adults

Kwon, Hyeok Choon; Woo, Seong Ill; Kim, Yeon Kyeong; Ahn, Sang Mi; Song, Kyoung Eun; Jung, Sun Hye; Kim, Dae Jung; Chung, Yoon Sok; Lee, Kwan Woo; Huh, Kap Bum

Abstract

OBJECTIVE
We investigated the cutoff values of surrogate measures of insulin resistance for diagnosing metabolic syndrome in Korean adults. RESARCH DESIGN and METHODS: This study was conducted as part of the Korean Metabolic Syndrome(KMS) Study. The data from 976 non-diabetic individuals(484 men and 492 women) aged 30~79 years were analyzed. We determined the odds ratios for the prevalence of metabolic syndrome according to the quartiles of fasting insulin, homeostasis model assessment for insulin resistance(HOMA-IR), and quantitative insulin sensitivity check index(QUICKI) as independent variables, while adjusting for age, sex, and body mass index. The areas under the receiver-operating characteristic(ROC) curves for fasting insulin, HOMA-IR, and QUICKI for increased metabolic syndrome were compared, and the cutoff values of fasting insulin, HOMA-IR, and QUICKI were estimated.
RESULTS
The cutoff points for defining insulin resistance are a fasting insulin level of 12.94micronU/mL, HOMA-IR= 3.04 as the 75th percentile value, and QUICKI = 0.32 as the 25th percentile value. Compared with the lowest quartile, the adjusted odds ratios for the prevalence of metabolic syndrome in the highest quartiles of fasting insulin, HOMA-IR, and QUICKI were 1.95(1.26~3.01), 2.27(1.45~3.56), and 2.27(1.45~3.56), respectively. The respective cutoff values for fasting serum insulin, HOMA-IR, and QUICKI by ROC analysis were 10.57micronU/mL(sensitivity 58.5%, specificity 66.8%), 2.34(sensitivity 62.8%, specificity 65.7%), and 0.33(sensitivity 61.2%, specificity 66.8%).
CONCLUSIONS
Fasting insulin, HOMA-IR, and QUICKI are good surrogate measures of insulin resistance in Korean non-diabetic adults. We suggest that the cutoff values using these simple methods could be applied to evaluate insulin resistance and predict metabolic syndrome in Korean non-diabetic adults.