Metabolic Score for Visceral Fat (METS-VF), a novel estimator of intra-abdominal fat content and cardio-metabolic health

Abstract

Intra-abdominal and visceral fat (VAT) are risk factors for the development of cardio-metabolic comorbidities; however its clinical assessment is limited by technology and required expertise for its assessment. We aimed to develop a novel score (METS-VF) to estimate VAT by combining the non-insulin-based METS-IR index, waist-height ratio (WHtr), age and sex. We developed METS-VF in a sample of 366 individuals with Dual X-ray absorptiometry (DXA). METS-VF was modeled using non-linear regression and validated in two replication cohorts with DXA (n=184, with n=118 who also had MRI) and bio-electrical impedance (n=991). We also assessed METS-VF to predict incident type 2 diabetes (T2D) and arterial hypertension independent of body-mass index (BMI) in our Metabolic Syndrome Cohort (n=6144). We defined METS-VF as: 4.466+0.011*(Ln(METS-IR))3+3.239*(Ln(WHtr))3+0.319*(Sex)+0.594*(Ln(Age)). METS-VF showed better performance compared to other VAT surrogates using either DXA (AUC 0.896 95% CI 0.847-0.945) or MRI (AUC 0.842 95% CI 0.771-0.913) as gold standards. We identified a METS-VF cut-off point >7.18 in healthy patients which has 100% sensitivity (95% CI 76.8-100) and 87.2% specificity (95% CI 79.1-93.0) to identify increased VAT (>100cm2). METS-VF also had adequate performance in subjects with metabolically-healthy obesity. Finally, in our metabolic syndrome cohort, subjects in the upper quintiles of METS-VF (>7.2) had 3.8 and 2.0-fold higher risk of incident T2D and hypertension, respectively (p<0.001). This effect was independent of BMI for both outcomes. METS-VF is a novel surrogate to estimate VAT, which has better performance compared to other surrogate VAT indexes and is predictive of incident T2D and hypertension. METS-VF could be a useful tool to assess cardio-metabolic risk in primary care practice and research settings.