#1462 Muscle mass, muscle strength, and health-related quality of life in kidney transplant recipients results of the TransplantLines Biobank & cohort study

Abstract

Abstract Background and Aims Muscles play a vital role in nearly every aspect of daily living, and kidney transplant recipients (KTR) often experience reduced muscle mass and strength, potentially contributing to their diminished health-related quality of life (HRQoL). We aimed to investigate the potential relationship of muscle mass and muscle strength with physical HRQoL in KTR. Method Data of stable KTR (≥1 year after transplantation) enrolled in the TransplantLines Biobank and Cohort Studies were used. Muscle mass was assessed using both appendicular skeletal muscle mass (via bioimpedance analysis) indexed to height squared (ASMI) and 24-hour urinary creatinine excretion rate indexed to height squared (CERI). Muscle strength was assessed using handgrip strength indexed to height squared (HGSI). HRQoL was assessed using the physical component score derived from the Short Form 36 questionnaire. Results A total of 751 KTR (61% male, mean age 56 ± 13 years) at a median of 3 years after transplantation were included. Mean ASMI was 7.5 ± 1.2 kg/m2, mean CERI was 4.1 ± 1.1 mmol/24 h/m2 and mean HGSI was 12.4 ± 3.4 kg/m2. The mean physical HRQoL score was 70 ± 21. Lower ASMI, CERI and HGSI were all associated with lower physical HRQoL, independent of potential confounders. Both associations were best characterized by a significant non-linear relationship (see Figure). Below median values, ASMI, CERI and HGSI were each associated with physical HRQoL, whereas above median values, associations were far less pronounced. When associations of ASMI, CERI and HSGI were adjusted for each other, associations of below median values of ASMI and CERI with physical HRQoL materially weakened, while those of HGSI remained strongly associated. Compared to the 50th percentile, a decrease to the 10th percentile was associated with a decrease in physical HRQoL of 6.0% for ASMI (P = 0.006), of 5.1% for CERI (P = 0.006) and 13.2% for HGSI (P < 0.001), whereas an increase to the 90th percentile was associated with an increase in physical HRQoL of only 1.3% for ASMI (P = 0.22), of 3.6% for CERI (P = 0.05) and −0.4% for HGSI (P = 0.73). Conclusion Our findings suggest that low muscle mass and muscle strength are potentially modifiable risk factors for impaired physical HRQoL. Both muscle mass and muscle strength were complementarily associated with HRQoL. However, muscle strength was most strongly associated with physical HRQoL. The non-linear nature of the associations implies that KTR with low muscle mass or strength may particularly benefit from (p)rehabilitation interventions to improve HRQoL.