Validation of risk prediction tools in elderly patients who initiate dialysis

Frailty Assessment Tools in Chronic Kidney Disease: A Systematic Review and Meta-analysis

Rationale & Objective

Frailty represents a loss of physiologic reserve across multiple biological systems, confers a higher risk of adverse health outcomes, and is highly prevalent among people with chronic kidney disease (CKD). We evaluated the measurement properties of frailty tools used in CKD and summarized the association of frailty with death and hospitalization.

Study Design

Systematic review and meta-analysis.

Setting & Study Populations

Studies assessing multidimensional frailty tools in adults at any stage of CKD and evaluating a measurement property of interest as per the Consensus-based Standards for the Selection of Health Measurement Instruments taxonomy.

Selection Criteria for Studies

Observational studies and randomized trials.

Data Extraction

Risk and precision measurements; measurement properties.

Analytical Approach

The Comprehensive Geriatric Assessment was the clinical standard for frailty identification. We pooled data using random effects models or summarized with narrative synthesis when data were too heterogenous to pool.

Results

We included 105 studies with data for at least one of the following: discriminative (n = 84; 80%), convergent (n = 20; 19%), and criterion validity (n = 2; 2%); responsiveness (n = 9; 9%) and reliability (n = 1; 0.1%). For the Fried Frailty Phenotype (FFP), the pooled adjusted HR (aHR) for mortality was 2.01 (95% confidence intervals [CI], 1.35-2.98; P = 0.001; I 2 = 58%) and 1.89 (95% CI, 1.25-2.85; P = 0.002; I 2 = 0%) for hospitalization in kidney failure (KF) populations. The pooled aHR for the Clinical Frailty Scale for mortality in pre-frail versus non-frail was 1.75 (95% CI, 1.17-2.60; I 2 = 26%) and 2.20 (95% CI, 1.00-4.80; I 2 = 66%) in frail versus non-frail. The Fatigue, Resistance, Ambulation, Illness, and Loss of weight scale showed consistent discriminative validity for higher mortality in non-dialysis CKD. The modified FFP (self-reported) showed acceptable discriminative validity and agreement with the FFP in patients with KF. In CKD and KF populations, agreement between clinicians' subjective impression of frailty and frailty tools was low.

Limitations

Few studies compared the accuracy of frailty tools to the Comprehensive Geriatric Assessment. Only 1 study reported reliability. Studies were of overall low-moderate quality.

Conclusions

The FFP and Clinical Frailty Scale showed acceptable discriminant validity for clinical outcomes, and the modified FFP is an alternative tool to use if direct measurements are not feasible. The evidence does not support the use of clinicians' subjective impression to identify frailty.

Usefulness of the Clinical Frailty Scale in patients with end-stage kidney disease

Background

The frailty index (FI) is commonly used to estimate frailty in end-stage kidney disease (ESKD) patients. The Clinical Frailty Scale (CFS) is a less time-consuming alternative. We aimed to determine the test performance of the CFS for pre-dialysis and dialysis patients and patients receiving conservative therapy from the Dialysis Centre Apeldoorn.

Methods

In this cross-sectional study, haemodialysis, peritoneal dialysis, pre-dialysis patients and patients receiving conservative therapy from the Dialysis Centre Apeldoorn were included and subjected to frailty assessment. Nephrologists not familiar with the CFS completed the frailty score after medical consultation. The sensitivity, specificity and area under the curve (AUC) of the CFS were determined. The FI was used as the gold standard.

Results

Included were 144 patients, of whom 60 (41.7%) were considered frail according to the FI. The mean age was 67.4 ± 13.5 years and 56 (38.9%) were female. The cut-off point of the CFS for 'vulnerable' (CFS ≥4) had a sensitivity of 63.3%, a specificity of 81.0% and an AUC of 0.72. The cut-off point of the CFS for 'frail' (CFS ≥5) had a sensitivity of 50.0%, a specificity of 91.7% and an AUC of 0.71.

Conclusions

The CFS is a quick and easy-to-use tool for the determination of frailty in ESKD patients with a high prevalence of frailty. Nevertheless, the sensitivity of the CFS in the present study was considered too low to implement into daily clinical practice. The sensitivity might be increased by training nephrologists in the use of the CFS.

Use of frailty assessment instruments in nephrology populations: a scoping review

BACKGROUND

Frailty is a clinical syndrome of accelerated aging associated with adverse outcomes. Frailty is prevalent among patients with chronic kidney disease but is infrequently assessed in clinical settings, due to lack of consensus regarding frailty definitions and diagnostic tools. This study aimed to review the practice of frailty assessment in nephrology populations and evaluate the context and timing of frailty assessment.

METHODS

The search included published reports of frailty assessment in patients with chronic kidney disease, undergoing dialysis or in receipt of a kidney transplant, published between January 2000 and November 2021. Medline, CINAHL, Embase, PsychINFO, PubMed and Cochrane Library databases were examined. A total of 164 articles were included for review.

RESULTS

We found that studies were most frequently set within developed nations. Overall, 161 studies were frailty assessments conducted as part of an observational study design, and 3 within an interventional study. Studies favoured assessment of participants with chronic kidney disease (CKD) and transplant candidates. A total of 40 different frailty metrics were used. The most frequently utilised tool was the Fried frailty phenotype. Frailty prevalence varied across populations and research settings from 2.8% among participants with CKD to 82% among patients undergoing haemodialysis. Studies of frailty in conservatively managed populations were infrequent (N = 4). We verified that frailty predicts higher rates of adverse patient outcomes. There is sufficient literature to justify future meta-analyses.

CONCLUSIONS

There is increasing recognition of frailty in nephrology populations and the value of assessment in informing prognostication and decision-making during transitions in care. The Fried frailty phenotype is the most frequently utilised assessment, reflecting the feasibility of incorporating objective measures of frailty and vulnerability into nephrology clinical assessment. Further research examining frailty in low and middle income countries as well as first nations people is required. Future work should focus on interventional strategies exploring frailty rehabilitation.