Anthropometric indices: How they compare in screening of cardio- metabolic risks in a Nigerian sub-population.

Background: The current anthropometric indices used for diagnosis of cardio-metabolic syndrome (CMS) in sub-Saharan Africa are those widely validated in the western world. We hereby aim to compare the sensitivity and specificity of these tools in identifying risk factors for CMS.

Method: The study assessed body mass index (BMI), waist circumference (WC) and waist-to-height ratio (WHtR). Statistical analyses were performed to determine the sensitivity and specificity of WHtR in comparison with WC cut-off points recommended by the International Diabetes Federation (IDF) and the Third Adult Treatment Panel (ATPIII) as well as BMI cut-offs prescribed by the World Health Organisation (WHO).

Result: WHtR had the highest area under the receiver operating characteristic (ROC) curve in screening CMS. WHtR >0.5 also showed highest sensitivity in both genders in identifying CMS and clusters of >2 CMS risk factors, but with lowest specificity and positive likelihood ratio (LR+). ATPIII WC cut-off revealed lowest sensitivity and highest specificity in screening CMS and >2 CMS risk factors in males (p<0.000l). IDF WC-threshold had the more stable sensitivity and specificity in males (p<0.0001) but not in females.

Conclusion: WHtR>0.5 is more sensitive than WC and BMI recommended values in screening for CMS, but with the least positive likelihood ratio. However, more studies in other nations of sub-Saharan Africa are needed to assure evaluation of different cut points that will yield optimal specificity and sensitivity. This will help curb the problem of over-diagnosis of CMS risk factors and increase better health outcome of the population.