Low Skeletal Muscle Mass Identifies Ultra-High Metabolic Risk in Slovak Children with Obesity: A Body Composition-Based Approach to Risk Stratification

Background: Childhood obesity demonstrates substantial metabolic heterogeneity. We determined insulin resistance prevalence in Slovak children with obesity using multiple validated markers and identified high-risk phenotypes. Methods: Cross-sectional study of 54 obese children (BMI 29.5±4.7 kg/m²) and 33 controls (BMI 20.6±1.9 kg/m²). All underwent bioelectrical impedance analysis and fasting metabolic profiling including HOMA-IR and triglyceride-to-HDL cholesterol (TG/HDL-C) ratio. Insulin resistance was defined as HOMA-IR >3.42 (obese) or >1.68 (controls), and TG/HDL-C >0.99 mmol/L. Age-matched sensitivity analysis was performed on 30 pairs. Results: Among obese children, 44.4% demonstrated HOMA-IR-defined insulin resistance versus 51.7% of controls using respective cut-offs, with significantly higher mean HOMA-IR (3.66±2.07 vs 2.53±2.55, p40%) characterized 24.1% of obese children, demonstrating 85.7% insulin resistance prevalence versus 30.0% without low muscle mass (p< 0.01), with HOMA-IR 1.52 points higher (95% CI: 0.31-2.73). Remarkably, 42.9% of children with low muscle mass showed concordant elevation of both metabolic markers versus 15.0% without (OR 4.25). Conclusions: Low skeletal muscle mass in obese Slovak children represents an ultra-high-risk phenotype with 85.7% insulin resistance prevalence and 4.25-fold increased odds of severe metabolic dysfunction. Age-matched analysis confirmed that metabolic differences are independent of age effects. Body composition-based risk stratification enables personalized interventions targeting the highest-risk children.