Skin fold thickness at abdomen: a simple anthropometric measurement may compliment metabolic syndrome definition in patients with normal waist circumference

Backgroud and Objectives Previous studies have reported that skin fold thickness (SF) strongly correlated with insulin resistance in the metabolic syndrome (MetS). In this study, we developed a MetS definition by SF at A8 point (SFA8) on Erdheim diagram(MetSSFA8) in essential hypertensive patients. Subjects and Methods Medical records of 268 essential hypertensive patients (126males and 122 females) were analyzed, including 210 non-diabetic patients (NDM group) and 58 patients with diabetes (DM group).The mean age was 61.4 ± 9.9 and 59.0 ± 11.0 years, respectively. The control group consisted of 90 non-diabetic, non-hypertensive patients with a mean age of 58.0 ± 11.3 years. The proposed MetSSFA8 definition included SFA8 specific values ( ≥30 mm in female and ≥27 mm in male) and at least two of the following: raised triglyceride levels ( ≥1.7 mmol/L), or specific treatment for this lipid abnormality; raised blood pressure (SBP≥130 mmHg and/or DBP≥85 mmHg), or treatment of previously diagnosed hypertension;reduced HDL-cholesterol (＜ 1.03 mmol/L in men, ＜1.29 mmol/L in women), or specific treatment for this lipid abnormality; raised fasting plasma glucose (≥5.6 mmol/l), or previously diagnosed DM. Metabolic Syndrome by the National Cholesterol Education Program and International Diabetes Federation definitions were determined with abdominal obesity defined by Asia-Pacific criteria for waist circumference (NCEPA and IDFA). Results The percentage of MetS as defined by NCEPA, IDFA and MetSSFA8 in NDM group was lower than that of NCEPA, IDFA and MetSSFA8 in DM group [OR=7.7 (95%CI, 2.9-20.2) and 2.5 (95%CI, 1.4-4.8) and 2.7(95%CI, 1.3-5.6), respectively] and higher than that of the control group [OR=53.3 (95%CI, 16.7-170.6), 5.8 (95%CI, 2.6-13.2) and18.8 (95%CI, 7.3-48.7), respectively]. The percentage of MetS by NCEPA, IDFA and MetSSFA8 in males in NDM group was lower than the percentage of MetS by NCEPA, IDFA and MetSSFA8 in females in NDM group (50.8% and 77.9%, P＜ 0.001; 15,9% and 67.2%, P＜ 0.001; 60.3% and 73.8%, P ＜0.05, respectively). In subjects with normal WC or both normal WC and BMI, the percentage of MetS by SFAS was higher than that the percentage of MetS by NCEPA (36.9% and 50.8%, P＜ 0.05 and 36.0% and 51.0%, P＜ 0.05).The sensitivity, specificity, false positive rate, positive predictive value, negative predictive value of MetSSFA8 assessed with NCEPA definitions were 0.87, 0.73, 0.27, 0.79 and 0.82, respectively. There was a close agreement betwee