Physical Frailty and Functional Status in Patients With Advanced Chronic Kidney Disease: A Systematic Review

BACKGROUND: With an aging population and growing number of patients with chronic kidney disease (CKD), integrating the latest risk factors when deciding on a treatment plan can result in better patient care. Frailty remains a prevalent syndrome in CKD resulting in adverse health outcomes. However, measures of frailty and functional status remain excluded from clinical decision making. OBJECTIVE: To examine the degree to which different measures of frailty and functional status are associated with mortality, hospitalization, and other clinical outcomes in patients with advanced CKD. DESIGN: Systematic review. SETTING: Observation studies including cohort study, case-control study, or cross-sectional study examining frailty and functional status on clinical outcomes. There were no restrictions on type of setting or country of origin. PATIENTS: Adults with advanced CKD, including both types of dialysis patients. MEASUREMENTS: Data including demographic information (e.g., sample size, follow-up time, age, country), assessments of frailty or functional status and their domains, and outcomes including mortality, hospitalization, cardiovascular events, kidney function, and composite outcomes were extracted. METHODS: A search was conducted using databases Medline, Embase, and Cochrane Central Register for Controlled Trials. Studies were included from inception to March 17, 2021. The eligibility of studies was screened by 2 independent reviewers. Data were presented by instrument and clinical outcome. Point estimates and 95% confidence intervals from the fully adjusted statistical model were reported or calculated from the raw data. RESULTS: A total of 117 unique instruments were found among 140 studies. The median sample size of studies was 319 (interquartile range, 161-893). Most studies focused on incident and chronic dialysis patient populations, with only 15% of studies examining non-dialysis CKD patients. Frailty and lower functional status were associated with an increased risk for adverse clinical outcomes such as mortality and hospitalization. The 5 individual domains of frailty were also found to be associated with poor health outcomes. LIMITATIONS: Meta-analysis could not be performed due to significant heterogeneity between studies and methods used to measure frailty and functional status. Many studies had issues with methodological rigor. Selection bias and the validity of data collection could not be ascertained for some studies. CONCLUSION: Frailty and functional status measures should be integrated to help guide clinical care decision making for a comprehensive assessment of risk for adverse outcomes among patients with advanced CKD. REGISTRATION (PROSPERO): CRD42016045251