#2947 Exploring various approaches for assessing fatigue in patients receiving hemodialysis using the CONVINCE study population
Authors: Schappert Anna , Fischer Felix , Liegl Gregor , Cromm Krister , Rose Matthias 
Published: May 2024

Abstract

Background and Aims
In nephrology, there is a growing interest in identifying patients’ priorities to achieve meaningful outcomes. A particular relevant outcome in end stage kidney disease is fatigue, with prevalence ranging from 60% to 97% in patients receiving hemodialysis. Different approaches for assessing fatigue exist. The objective of this study was to investigate how self-reported peri-/intra-dialytic and post-dialysis fatigue relate to overall fatigue levels and to certain risk factors of patients receiving hemodialysis.

Method
The CONVINCE trial is an international multi-center, prospective, randomized, open label, controlled trial, comparing all-cause mortality of high-flux hemodialysis with high-dose hemodiafiltration. Patient-related outcomes (PROs) were examined as secondary outcomes. Fatigue was assessed using tailored short forms from the Patient-Reported Outcome Measurement Information System (PROMIS) to measure overall fatigue, the newly developed Convince Dialysis Fatigue Scale (CDFS) to capture peri-/intra-dialytic fatigue and the Convince Time to Recovery (CTTR-1) to measure post-dialysis fatigue. PROs were collected every 3 months for 24 months, except for CTTR-1 and a PROMIS fatigue short form, which were collected on a monthly basis from the 1st to 5th months.
To investigate the agreement between overall fatigue, peri-/intra-dialytic and post-dialysis fatigue, Spearman's correlation was calculated. In addition, we examined whether general health, depression, physical function, sex and dialysis vintage were related to peri-/intra-dialytic, post-dialysis and overall fatigue in a cross-sectional study design (irrespective of dialysis modality). To test for change over time as well as differences between groups Cohen's d effect sizes were calculated.

Results
Data for PROs was collected from 1282 participants at baseline and 804 after 24 months. The PROMIS fatigue score and the CDFS correlated strongly at each measurement point (Spearman r≥0.67). The PROMIS fatigue score and CTTR-1 correlated moderately (Spearman r≥0.41). We found large effect sizes for mean differences for peri-/intra-dialytic fatigue between patients with/without at least mild depression (Cohen's d 1.27 (95%CI 1.11 to 1.44)) as well as between patients with/without at least moderately impaired physical function (Cohen's d 1.04 (95% CI 0.89 to 1.19)). Patients, who reported CTTR-1 ≥12 hours, showed also large effect sizes for mean differences for overall fatigue between patients with/without at least mild depression (Cohen's d 0.9 (95% CI 0.48 to1.39)) as well as between patients with/without at least moderately impaired physical function (Cohen's d of 1.1 (95% CI 0.7 to 1.67)). In almost half of the patients, the time to recovery was &gt; 4 hours, and patients who reported having to recover for a longer time after dialysis were, on average, more fatigued overall.
Overall fatigue, with an observed mean change of 2.10 (SD 9.69) of PROMIS fatigue score, and peri-/intra dialytic fatigue, with an observed mean change of 1.98 (SD 6.98) of CDFS, showed a small increase over the study course. Prevalence of clinically relevant overall fatigue, as defined by a PROMIS fatigue score ≥59, was 15.9% at baseline and increased to 19.8 % after 24 months.

Conclusion
The three fatigue measurements correlated moderately to strongly and showed small change over time. The relations of various risk factors with fatigue, including self-reported depression, were similar, irrespective of the measure used, indicating that the discrimination between these constructs is imperfect. Furthermore, we discovered that the overall level of fatigue in the study population was comparable to the general population and the prevalence of clinically relevant fatigue was less than reported previously. This is surprising, given the emphasis on fatigue as a significant outcome for patient receiving dialysis. To assess the experience and impact of fatigue in patients receiving hemodialysis, greater attention is warranted, particularly in the timing of fatigue, the time span studied, and the severity of fatigue, especially when investigating a specific fatigue treatment.