Concordância entre medidas de membros superiores e inferiores para identificar idosos com baixa força, massa e qualidade muscular

Abstract

Introduction: during the aging process there is a decline of muscle strength (MS), muscle mass (MM) and muscle quality (MQ). These declines are associated with adverse health events. There are recommendations to evaluate of MS, MM and MQ in upper (UL) and lower limbs (LL). However, it is not clear whether there is agreement between measures of UL and LL to identify elderly people with low MS, MM and MQ. Objective: to evaluate the agreement between measures of UL and LL to identify elderly people with low MS, MM and MQ. Methods:participants (n = 385; age 66.1 ± 5.1 years; 72.4% women) performed the handgrip strength tests (HGS) and the chair-stand-test in 30s (CST) to assess MS of UL and LL, respectively. The total MM of the arms and legs was determined by the absorption of dual energy X-rays (DXA). The QM was determined in three ways: i) ratio between the performance in the MS tests and the relative total MM (%); ii) ratio between the performance in the MS tests and absolute total MM (kg); iii) ratio between the performance in the MS and absolute MM tests of MS and MI. The agreement analysis was performed between the i) MS tests; ii) MM of the arms and legs iii) QMof UL and LL. Values below the 25th percentile, stratified by sex and age group (60-69 and 70-80 years), were used to identify elderly people with low MS, MM and QM. Kappa statistic was used for concordance analysis and we adopted p <0.05 for all analyzes. Results: There was moderate agreement in the low MM (kg) between arms and legs (Kappa coefficient = 0.473; 95% CI: 0.371 - 0.574; p = 0.001). There was low agreement in the low MQ calculated by the total MM (kg) between MS and MI (Kappa coefficient = 0.238; 95% CI: -0.114 - 0.361; p = 0.002) and in the low MQ calculated by MM (kg) between arm and leg (Kappa coefficient = 0.206; 95% CI: -0.082 - 0.330; p = 0.005). There was no agreement on low MS between the HGS test and the 30s CST (Kappa coefficient = 0.04; 95% CI: 0.093 - 0.185; p = 0.352) and low MQ calculated by the percentage of MM (%) between UL and LL (Kappa coefficient = 0.052; 95% CI: -0.074 to 0.178; p = 0.301). Conclusion: Measures of UL and LL have low to moderate agreement to identify elderly people with low MM and absolute MQ (kg), however they do not show agreement to identify elderly people with low MS and relative MQ (%). Therefore, measures of UL and LL can generate different interpretations to identify elderly people with low MS, MM and QM.