Low Estimated Glomerular Filtration Rate (eGFR) is Associated with Skeletal Muscle Function Deficit in Elderly Persons

Abstract

Physical performance is closely associated with chronic diseases and dysfunction of numerous organ systems. Old persons with chronic renal failure have shown the apparent decline in physical performance, especially in the end-stage. However, it is unclear whether the subclinical kidney dysfunction is associated with skeletal muscle function deficit in the elderly population. PURPOSE: To determine the association between renal function and skeletal muscle function deficit in old persons without nephropathy. METHODS: Eight hundred fifty-four Korean elderly (female, 75.3%) aged 65 to 89 years were included in this cross-sectional study. All participants were interviewed face-to-face and received measure of anthropometry, body composition and serum biomarkers of metabolic diseases. eGFR was calculated using the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation based on serum creatinine concentration. The following physical performance tests were performed: handgrip strength (absolute and relative values), timed up-and-go (TUG), chair stand, 2 min stationary walking, figure-eight walk and sit-and-reach. Skeletal muscle function deficit was defined as a combination of weakness and slowness based on the relative handgrip strength (men <1.32, women <0.792) and converted TUG to walking speed (<0.8 m/s), respectively. RESULTS: Of the subjects, the prevalence of 30≤ eGFR <45 mL/min/1.73m2 was 16.2%. The subjects with 30≤ eGFR <45 mL/min/1.73m2 showed significantly lower physical performance for muscular strength and functional mobility than those with 45≤ eGFR <60 and eGFR ≥60 mL/min/1.73m2, respectively (all for p<0.05). Multinomial (polychotomous) logistic regression analysis, with three categories of eGFR as the dependent variable, showed the significant association between eGFR and skeletal muscle function status even after adjustment for potential confounders (odds ratios [95% CI] were 4.8 [1.3-17.2] for a GFR of 45 to 59, 12.9 [3.1-52.9] for above 60 mL/min/1.73m2, p for trend <0.01). CONCLUSION: Taken together, skeletal muscle function status is associated with even moderately reduced eGFR in an older population. This finding suggests that maintenance of physical and functional fitness may be a contributory factor for preserving renal function in elderly persons.