Decline in measured glomerular filtration rate is associated with a decrease in endurance, strength, balance and fine motor skills

AIM: Physical performance in chronic kidney disease affects morbidity and mortality. The aim was to find out which measures of physical performance are important in CKD and if there are associations with declining measured GFR.

METHODS: Endurance was assessed by 6-minute walk test (6-MWT) and stair climbing, muscular endurance by 30-seconds sit to stand, heel rises and toe lifts, strength by quadriceps- and handgrip strength, balance by functional reach and Berg´s balance scale, and fine motor skills by Moberg´s picking-up test. GFR was measured by Iohexol clearance.

RESULTS: The study comprised 101 patients with CKD 3b-5 not started dialysis, 40 women and 61 men, with a mean age of 67 ± 13 (range: 22 - 87) years. All measures of physical performance were impaired. A decrease in GFR of 10 ml/min/1.73 m(2) corresponded to a 35 metre shorter walking distance in the 6-MWT. Multivariable linear regression analysis showed significant relationships between decline in GFR and the 6-MWT (p = 0.04), isometric quadriceps strength left (p = 0.04), balance measured as functional reach (p = 0.02) and fine motor skills in the left hand as measured by Moberg´s picking-up test (p = 0.01), respectively, after sex, age, comorbidity and the interaction between sex and age had been taken into account.

CONCLUSION: Endurance, muscular endurance, strength, balance and fine motor skills were impaired in patients with CKD 3b-5. Walking capacity, isometric quadriceps strength, balance, and fine motor skills were associated with declining GFR. The left extremities were more susceptible to GFR, ageing and comorbidities and seem thus to be more sensitive.