A new formula for screening metabolic syndrome in Asians: skin fold thickness at A8 point on Erdheim diagram and waist circumference

Background and objectives Recent studies have shown that abdominal obesity is an important component for the diagnosis of metabolic syndrome (MS) and MS is a high risk factor for cardiovascular disease and diabetes mellitus. The aim of this study was to develop a new formula for screening and diagnosis of MS using the waist circumference (WC) and skin fold thickness at the point A8 (SFA8) on the Erdheim diagram. Methods A total of 358 essential hypertensive patients (189 male and 169 female) with a mean age of 59.0±9.7 years were included; 151 healthy people (79 male, 72 female) with a mean age of 57.3± 12.1 years (similar to hypertensive patients) who were non-hypertensive and non-diabetic served as a control group. All subjects had no evidence of hepatic, renal, or endocrine disease as determined by history, physical examination and screening blood tests. Height, weight, WC, SFA8, blood pressure (BP), fasting plasma glucose, HDL-cholesterol and triglyceride levels were measured in all subjects. Abdominal obesity measured by WC using the Asia-Pacific criteria (IDFA) was applied for meeting the MS definition. The normal value of SFA8 was measured in the non-MS group. Relationships between SFA8 and systolic BP, diastolic BP, fasting plasma glucose, HDL-cholesterol and triglyceride levels were calculated in the control group. A new formula was developed according to high SFA8 and high WC. Results The normal value of SFA8 in non-MS group was 23.6±7.2 mm in male and 26.5±4.6 mm in female, respectively. The value of SFA8 in MS group was 36.7± 7.4 mm in male and 38.9 ± 8.1 mm in female, respectively. The value of WC in MS group and non-MS group were 92.5±3.0 cm and 79.4±6. 1 cm in male and 86.3±6.4 cm and 74.7±5.4 cm in female, respectively. There was a correlation between SFA8 and systolic BP, diastolic BP, fasting plasma glucose, HDL-cholesterol and triglyceride in control group (the correlation coefficients were 0.29, 0.23, 0.25, -0.31 and 0.46, respectively, P 90 cm in male, > 80 cm in female) + high SFA8 (> 30 mm). The sensitivity, specificity, false positive rate, false negative rate, positive predictive value, and negative predictive value of the new formula assessed with the IDFA definition were 94%, 93%, 7%, 6%, 92% and 95%, respectively. The percentage of all patients who met the criteria for MS by conventional definition was 46.2%. The percentage of all patients who met the criteria by the new-definition was 47.0%. There was no difference between the prevalence percentage of the MS according to new criteria and the IDFA criteria in all patients, in male and in female, respectively (P > 0.05). Conclusion This new formula for MS might be useful for easy screening. The advantage over current criteria is the lack of need for laboratory testing.