Waist circumference cut-off point determination for defining metabolic syndrome among type II diabetic mellitus patients at Ayder comprehensive specialized hospital, Mekelle University, Tigray region, Northern Ethiopia

Abstract

Background: Metabolic syndrome(MetS) is a complex disorder which is characterized by clustering of interrelated risk factors of cardiovascular disease and diabetic mellitus. So far, cutoff point variability for one of the cluster to define MetS, which is waist circumference, based on ethnicity was documented. Objective: To determine waist circumference cutoff point to define MetS among type II diabetic patients. Methods: Institution based cross sectional study was conducted from March to April 2017 at Ayder Comprehensive Specialized Hospital among type II diabetic mellitus (T2DM) patients. Systematic sampling technique was used to select study participants and 520of them were assumed to be included in the study. Data were collected by checklist, anthropometric measurements and biochemical analyses. Fasting blood sample was collected for the biochemical evaluation. Data were entered to Epi-info3.5.1and transferred to SPSS20 for analysis. Participants having more than one abnormal MetS components were categorized as cases. The classification power of waist circumference (WC)to distinguish cases from controls was determined by ROC curve analysis. WC cutoff point was determined by taking the point which was having maximum Youden Index. Results: A total of 520 participants were included in the study, of whom308(59.2%) were females. The mean age of the participants was56 ± 10.8 years and 55 ± 11.4 years for males and females respectively. The classification power of WC was0.67(0.58-0.75) for male and 0.63 (0.52-0.73) for females. The optimal waist circumference cutoff point to predict the presence of at least two other components of the MetS was 95.5 cm(sensitivity39.8%, specificity86.3%, p value< 0.001)for males and 87.5 cm(sensitivity73.1%, specificity54.5%,p value< 0.017)for females. Conclusion: The power of WC value to classify cases from controls was poor and the cutoff points of WC were 87.5 cm and 95.5 cm for female and male respectively. WC cut-off points need to be reconsidered for these patients using a prospective cohort study. In addition, studies which can consider the confounders such as lipid lowering medications, age of the participants and duration of diabetes are advisable in order to increase the classification power of WC.