Associations between muscle quality index and cardiac function in older adults with sarcopenia and obesity

BACKGROUND: The increasing co-occurrence of sarcopenia and obesity is associated with morbidity. The muscle quality index (MQI), which measures strength per unit of muscle mass, has been described to detect sarcopenic obesity, but associations with cardiac function are unknown. METHODS: Adults without cardiovascular disease (CVD) underwent assessment for appendicular skeletal mass (ASM), handgrip strength (HGS), aerobic capacity (VO2 max, ml/kg/min), echocardiography (mitral early diastolic inflow velocity to annular tissue velocity [E/e’], early to late diastolic inflow velocity [E/A] ratios). Low MQI (HGS divided by upper body ASM) was defined as males < 5.76 kg/kg, females < 5.475 kg/kg. RESULTS: Participants (n = 574) were 66.3 ± 13.0 years old; 11.8% had obesity. Low MQI was present in 34.3%. The low MQI group was older than the normal MQI group (69.0 ± 10.4years vs. 64.8 ± 14.0years, p < 0.0001), with higher BMI (25.4 ± 3.8kg/m2 vs. 22.7 ± 3.1kg/m2, p < 0.0001). The low MQI group had greater left ventricular mass (129 ± 45 g vs 114 ± 44 g, p < 0.0001), left atrial volumes (37 ± 14 ml vs 33 ± 13 ml, p = 0.001), and greater diastolic dysfunction, evidenced by lower E/A (0.89 ± 0.28 vs 1.1 ± 0.49, p < 0.0001) and higher E/e’ (8.63 ± 2.42 vs 8.00 ± 2.58, p = 0.005). Low MQI group had lower VO2 max than the normal MQI group (33 ± 5.7 vs 36 ± 6.7 ml/kg/min, p < 0.0001). On multiple regression, low MQI was independently associated with lower E/A (β=-0.119, p < 0.0001) and VO2 max (β=-0.137, p < 0.0001). CONCLUSION: Low MQI is associated with diastolic dysfunction (reflected by lower E/A) and poorer aerobic capacity.