ABSTRACT: Background:The prevalence of frailty is disproportionately increased in patients with chronic kidney disease (CKD) in comparison with non-CKD counterparts and is the highest in patients on hemodialysis (HD). While the cross-sectional measurement of frailty on HD has been associated with adverse clinical events, there is a paucity of data on longitudinal assessment of frailty and its relationship to outcomes. Objective:The objectives were to (1) evaluate changes in frailty status, level of independence, mood, cognition, and quality of life (QoL) over a 12-month period and (2) explore the relationship between frailty status and level of independence, mood, cognition, and QoL at 2 different time points (at baseline and at 1 year). Design:This is a prospective cohort study involving 100 prevalent HD patients. Setting:Regina General Hospital and Wascana Dialysis Unit in Regina, Saskatchewan, Canada, between January 2015 and January 2017. Patients:One hundred prevalent HD patients underwent frailty assessments using the Fried criteria at baseline and 1 year later. Measurements:Frailty was assessed using the Fried criteria, which included assessments of unintentional weight loss, weakness (handgrip strength), slowness (walking speed), and questionnaires for physical activity and self-perceived exhaustion. Cognition, mood, and QoL were measured using questionnaires (Montreal Cognitive Assessment [MoCA], Geriatric Depression Scale [GDS], and EuroQol [EQ-5D] utility scores and visual analog scale [VAS], respectively). Methods:Frailty status was reported as a binary variable: frail vs. nonfrail (prefrail and robust). Differences across baseline and 1-year groups were assessed using McNemar's test or Wilcoxon signed-rank test, as appropriate. We assessed the differences between frail and nonfrail groups using the Mann-Whitney U test or chi-square test/Fisher's exact test where appropriate. Results:Ninety-seven of the 100 patients had complete initial assessments. The median (interquartile range [IQR]) duration of dialysis at baseline was 35.5 (13.75-71.75 months). One year later, 22 had died, 10 refused assessments, and 3 had relocated. In comparison with baseline vs 1 year, the number of frail patients was 68.1% vs. 67.7%; prefrail 26.8% vs. 26.1%; robust 5.1% vs. 6.2%; MoCA ?24, 69% vs. 64.5%; GDS score ? 2, 52.8% vs. 47.7%; median EQ-5D utility score 0.81 vs. 0.77; and median EQ-VAS 60 vs. 50. Similarly, in comparison with baseline vs. 1 year, the number of independent patients was 82% vs. 63%, independent with support 17% vs. 31%, and long-term care home 0% vs. 3.1%. Eighteen of the 22 patients (82%) who died were frail. At 1 year, the median (IQR) MoCA was 24 (19-25) vs. 25 (21-26; P = .039) and median (IQR) GDS was 2 (1-3) vs. 1(0-2; P = .034). Likewise, median (IQR) EQ-5D utility score was 0.78 (0.6-0.82) vs. 0.81 (0.78-0.85; P = .023). There were significant changes in self-care (27% vs. 0%), P = 0.006, and daily activities (68.2% vs. 38.1%), P = 0.021. Limitations:This is a single-center study, so direct inferences must be interpreted in the context of the demographics of the study population. Patients were undergoing dialysis for a median of 36 months before undergoing initial assessment. Conclusions:Frailty and prefrailty in our dialysis patients is near-ubiquitous and will need to be proactively addressed to improve subsequent health care outcomes.