Association between cardiorespiratory fitness and muscle strength in maintenance hemodialysis patients / 中华肾脏病杂志

ABSTRACT

Objective:To investigate the association between cardiorespiratory fitness (CRF) and muscle strength, and the influencing factors of CRF in maintenance hemodialysis (MHD) patients.Methods:It was a single-center cross-sectional study. Patients who were treated with regular MHD from September 1, 2020 to December 31, 2020 were recruited. Baseline data of MHD patients including body circumference (upper arm circumference of non-fistula, triceps skinfold thickness, and calf circumference), exercise capacity [6-min walking test (6MWT), timed up and go test (TUGT)] and upper and lower limb muscle strength (grip strength, knee extension strength) as well as clinical and biochemical data, Charlson comorbidity index were collected or measured. Cardiopulmonary exercise test (CPET) was used to test peak oxygen consumption per kg body weight (peakVO 2/kg) for reflecting CRF. Pearson correlation or Spearman correlation was used to analyze the correlation between peakVO 2/kg and clinical parameters. Multiple linear regression analysis (stepwise) was performed to analyze the influencing factors of peakVO 2/kg. Results:A total of 48 patients were enrolled in the study, of whom 34 were males (70.8%). The age was (60.31±10.44) years old. The median dialysis duration was 48(15, 84) months, and the peakVO 2/kg was (12.37±2.71) ml·kg -1·min -1, which was well below the normal value of 30-50 ml·kg -1·min -1. Furthermore, peakVO 2/kg was positively correlated with lower extremity muscle strength ( r=0.322, P=0.026) and 6MWT ( r=0.307, P=0.034), and negatively correlated with age ( r=-0.300, P=0.038). Multiple linear regression analysis demonstrated that lower extremity muscle strength ( β=0.241, P=0.009) and age ( β=-0.235, P=0.022) were the influencing factor of peakVO 2/kg. Conclusions:CRF of MHD patients is significantly decreased. The decrease of lower extremity muscle strength is an influencing factor of CRF reduction.