Evaluation of effect of cooled haemodialysis on cognition in patients with end-stage kidney disease (ECHECKED) feasibility randomised controlled trial results.

Background: Cognitive impairment is common in haemodialysis patients with no known beneficial interventions. Cooler dialysate slows brain white-matter changes, but its effect on cognition is unknown. This feasibility trial was performed to inform a fully-powered, randomised trial to assess this.

Methods: We aimed to randomise (1:1) 90 haemodialysis patients to this double-blinded, randomised controlled feasibility trial to standard care (dialysate-temperature 36.5 °C) or intervention (35 °C). Eligible patients were adult chronic haemodialysis recipients with no established diagnosis of dementia or psychiatric disease. The primary outcome was change in Montreal Cognitive Assessment (MoCA) score at 12-months. Secondary outcomes included recruitment and attrition rates, reasons for non-recruitment, intradialytic hypotension, depression, patient burden, computerised cognition test battery, and quality of life.

Findings: Of 334 patients screened, 160 were eligible. 99 declined mainly for the extra non-dialysis day study visits. Sixty-one patients consented, 43 randomised - 20 in standard care, 23 in intervention arms; 13 withdrew for non-dialysis day visits and 5 without reason before randomisation. 27 patients (12 standard care, 15 intervention) completed the trial - 5 died, 1 transplanted, 4 withdrew consent, and 6 could not attend due to the pandemic. Low temperature dialysis was well tolerated. There was no difference in change in MoCA from baseline to 12 months between the standard and intervention arms; 1.0 (-2.8-3.0, p = 0.755) and - 2.0 (-1.0 - -4.0, p = 0.047) respectively. There were no differences between groups on any secondary measures. There were no significant adverse events reported.

Discussion: The trial was significantly affected by the COVID-19 pandemic contributing to an attrition rate of 27%. The non-dialysis day research visits were mainly responsible for low recruitment and consent withdrawal. There are several learning points, described in the article, which will inform design of definitive trials in this area in the future.

Trial registration: ClinicalTrials.gov Identifier NCT03645733. Registration date 24/08/2018.