Relationships between cystatin C- and creatinine-based eGFR in Japanese rural community-dwelling older adults with sarcopenia

Abstract Background Sarcopenia is prevalent in patients with chronic kidney disease (CKD). Sarcopenia is prevalent in patients with chronic kidney disease (CKD). The indices of physical function, such as grip power and gait speed, decreased according to the decline in estimated glomerular filtration rate (eGFR). Methods We examined the relationships between cystatin C-based GFR (eGFRcys), and creatinine-based GFR (eGFRcre), and their ratio (eGFRcys/eGFRcre) and low skeletal muscle mass index (SMI) in community-dwelling older adults in Japan. This cross-sectional study included 286 men aged 73.3±6.2 years and 606 women aged 72.9±5.8 years from a rural area in Hyogo Prefecture, Japan. eGFRcys and eGFRcre were simultaneously measured, whereas low SMI based on the AWGS criteria was evaluated. Results eGFRcys and the eGFRcys/eGFRcre were significantly correlated with grip power and gait speed. The eGFRcys/eGFRcre was also correlated with SMI. In the multivariate logistic regression analysis, when the eGFRcys/eGFRcre was added as a covariate to the basic model, it was significantly associated with low SMI, both in all subjects. Moreover, CKDcys with a low eGFRcys/eGFRcre ratio (<1.0) was associated with a higher risk of low SMI than CKDcys alone. Conclusion In conclusion, CKDcys but not CKDcre is an independent risk factor of low SMI. In patients with CKDcys, lower eGFRcys/eGFRcre may be a practical screening marker of low SMI in community-dwelling older adults.