Personalised cooler dialysate for patients receiving maintenance haemodialysis (MyTEMP): a pragmatic cluster-randomised trial

Background — Conventionally, healthcare centres have provided maintenance haemodialysis using a 15 standard dialysate temperature (e.g., 36·5°C) for all patients. Many centres now use cooler dialysate (e.g. 36°C or lower) for potential cardiovascular benefits. The MyTEMP trial assessed whether personalised cooler dialysate, implemented as centre-wide policy, reduced the risk of cardiovascular-related deaths and hospitalisations compared with standard-temperature dialysate.

Methods — MyTEMP was a pragmatic, two-arm, parallel-group, registry-based, open-label, cluster-randomised, superiority trial done at 84 of Ontario’s 97 haemodialysis centres (Canada). Using covariate-constrained randomisation, we allocated 84 centres (1:1) to use either (1) personalised cooler dialysate (nurses set the dialysate temperature 0·5–0·9°C below each patient’s measured pre-dialysis body temperature, with a lowest recommended dialysate temperature of 35·5°C), or (2) standard-temperature dialysate (36·5°C for all patients and treatments). The primary composite outcome was cardiovascular-related death or hospital admission with myocardial infarction, ischaemic stroke, or congestive heart failure during the four-year trial period. The key secondary outcome was the mean  drop in intradialytic systolic blood pressure. Analysis was by intention to treat. The study is registered at ClinicalTrials.gov, NCT02628366.

Findings — Between April 3, 2017 and March 31, 2021, the 84 centres provided outpatient maintenance haemodialysis to 15 413 patients (~4·3 million haemodialysis treatments). The mean dialysate temperature was 35·8°C in the cooler dialysate group versus 36·4°C in the standard-temperature group. The primary outcome occurred in 1711 of 8000 patients (21·4%) in the cooler dialysate group versus 1658 of 7413 patients (22·4%) in the standard-temperature group; adjusted hazard ratio, 1·00 (96% CI, 34 0·89 to 1·11; p=0·93). The mean drop in intradialytic systolic blood pressure was 26·6 mm Hg versus 27·1 35 mm Hg, respectively; mean difference, -0·5 mm Hg; 99% CI -1·4 to 0·4 (p=0·14).

Interpretation — Centre-wide delivery of personalised cooler dialysate versus standard-temperature dialysate did not significantly reduce the risk of major cardiovascular events. The rising popularity of cooler dialysate is called into question by this study.