The impact of frailty and severe cognitive impairment on survival time and time to initiate dialysis in older adults with advanced chronic kidney disease: a prospective observational cohort study

Abstract

Background and objectives Frailty and cognitive impairment significantly impact survival time and time to initiate dialysis in older adults with advanced chronic kidney disease (CKD). This study aims to evaluate the effects of frailty and cognitive impairment on these outcomes and determine the most effective assessment tool for predicting early dialysis initiation and short survival time. Materials and methods This prospective observational cohort study involved 240 patients aged >= 65 years with stage 4 or 5 CKD, recruited from a nephrology outpatient department (ambulatory care) between March 2020 and March 2021. Frailty was assessed using the Physical Frailty Phenotype (PFP), PRISMA-7, Clinical Frailty Scale (CFS), and FRAIL scale. Cognitive function was evaluated using the Montreal Cognitive Assessment (MoCA). The primary outcomes were time to initiate dialysis and survival time, with secondary outcomes including hospitalization rates, length of stay, and mortality after dialysis initiation. Results Frail patients only showed significantly shorter time to dialysis initiation when identified by the PFP and FRAIL scale (28.3 months for frail vs. 31.2 months for non-frail, p = 0.028;26.9 months for frail vs. 30.9 months for non-frail, p = 0.038). The PFP, FRAIL, and CFS tools indicated significantly shorter survival times for frail patients compared to non-frail patients (26.8 months for frail vs. 30.6 months for non-frail, p = 0.003). Frailty is strongly correlated with severe cognitive impairment, as 45.5% of frail patients (according to the FRAIL scale) have dementia compared to 15.1% of non-frail patients (p<0.001). However, cognitive impairment did not significantly affect the time to dialysis initiation or survival time. Hospitalization rates and length of stay in the hospital were significantly higher only for frail patients identified by PRISMA-7, with a median hospital length of stay of 9.15 days for frail patients vs 6.37 days for non-frail patients (p = 0.044). Overall, 37.5% of the patients did not survive during the study follow-up, with frail patients having a higher mortality rate. Conclusion Frailty, mainly when assessed by PFP and FRAIL, is a significant predictor of early dialysis initiation and reduced survival time in older adults with advanced CKD. Cognitive impairment, while prevalent, did not independently predict these outcomes. Regular frailty screening should be incorporated into CKD management to tailor interventions and improve patient outcomes.