Association Between Estimated Glomerular Filtration Rate Based on Cystatin C and Grip Strength in Community-Dwelling Japanese Older Adults

Background: Kidney dysfunction is associated with sarcopenia. Estimated glomerular filtration rate based on cystatin C (eGFR(cys)), an alternative to creatinine-based measures of kidney function eGFR, is not affected by muscle mass. Given that the association of eGFR(cys) with muscle weakness would be limited, we examined the association in older adults with normal or compromised kidney function. Methods: This cross-sectional study involved 594 community-dwelling Japanese adults aged >= 40 years living in Yuzawa, Japan. Serum creatinine, cystatin C, and handgrip strength were concurrently measured at a health-check examination in 2015. eGFR was calculated according to the equation developed for the Japanese population using creatinine and cystatin C. Associations of eGFR(cys) and eGFR(creat) with low grip strength (men, <26 kg and women, <18 kg) were analyzed using logistic regression models adjusted to control for potential confounders. Results: Participants (mean age, 74.9 years) included 319 women and 109 individuals with low grip strength. Mean eGFR(cys) was 75.2 (SD 18.6) mL/min/1.73 m(2). Pearson's correlation coefficients of handgrip strength for eGFR(cys) and eGFR(creat) were 0.19 (p < .001) and -0.04 (p = .281), respectively. Multivariate logistic regression analysis showed the adjusted odds ratio (OR) of low grip strength for the highest versus lowest quartile of eGFR(cys) value was 2.46 (95% confidence interval, 1.03-5.86; p-trend = .026); whereas the comparative adjusted OR for eGFR(creat) was 0.67 (95% confidence interval, 0.34-1.32). Conclusions: Low kidney function as assessed by eGFR(cys) was associated with muscle weakness in community-dwelling Japanese older adults.

Automated summary

This study found a significant association between low kidney function assessed by eGFR(cys) and muscle weakness in community-dwelling Japanese older adults.