Cooler dialysate fails to cut major cardiovascular event or death, MyTEMP trial suggests

Haemodialysis has traditionally been conducted with dialysate of a temperature of 36.5°C, but the use of a personalised, lower-temperature dialysate is experiencing “rising popularity” with clinicians. Amit Garg (Western University, London, Canada) is corresponding author of the MyTEMP trial, an investigation into lower-temperature dialysate’s effectiveness, who recently presented at American Society of Nephrology (ASN) Kidney Week. The full results of the trial have now followed, published in The Lancet.

The study was performed across 84 haemodialysis centres across Ontario, Canada. Of these, half were assigned to use dialysate set to a standard temperature (36.5°C), while the other half used dialysate at a personalised lower temperature, 0.5–0.9°C cooler than the patient’s body temperature—as determined before the therapy—with a minimum temperature of 35.5°C.

In total, more than 15,000 patients’ outcomes were recorded by the study, making this the largest haemodialysis care study to date in terms of number of participants. The trial was not double-blind. Instead, the primary outcomes were collected as part of routine care “by medical coders who were unaware of the trial or the centres’ group assignment.”

The primary outcome after the four-year trial period was a composite one including “cardiovascular-related death or hospital admission with myocardial infarction, ischaemic stroke, or congestive heart failure.” The composite outcome occurred in 22.4% of patients in the standard temperature dialysate group and 21.4% in the cooler dialysate group—a finding which was not considered statistically significant. The team also found no significant difference in the average drop in systolic blood pressure during dialysis between the two groups, with “26.6 mm Hg in the cooler dialysate group and 27.1 mm Hg in the standard temperature group.”

The study authors concluded that “centrewide delivery of cooler dialysate” did not offer better outcomes to patients on the evidence they found. They said that the trend of increasing use of cooler dialysate may do little to prevent cardiovascular events, and that “the risks and benefits of cooler dialysate in some patient populations should be clarified in future trials.”

Speaking to Renal Interventions, Garg said that “what is remarkable about the MyTEMP trial is the tremendous support of our community and the methods we used. With this support we embedded the trial into existing healthcare at nearly all haemodialysis centres in Ontario, we were able to determine whether the intervention would improve outcomes in a real-world setting that represented all patients who receive haemodialysis in routine care. The trial was strongly supported by the Ontario Renal Network and helps realise the goal of a learning healthcare system.” suggested incremental implementation did not change the risk of patient hospitalisation, while two randomised controlled trials suggested it decreased it, and one study suggested it increased it.

Haemodialysis (HD) is traditionally implemented in four-hour sessions, three times a week. The efficiency of this approach has been questioned, however, by the authors of a new study published in Nephrology Dialysis Transplantation. Led by Emma Caton (School of Life and Medical Sciences, Hatfield, UK), it looked at whether it benefitted end-stage kidney disease (ESKD) patients to have their dialysis sessions gradually increased in line with the progression of their condition.

HD PATIENTS OFTEN SHOW disproportionately high rates of mortality in the first few months of treatment, said the study authors. The prevailing style of HD implementation poses difficulty in adjusting to the treatment for patients, who “may benefit from a gentler start to dialysis.”

Incremental HD starts patients on lower doses tailored to the specific stage of their illness, measured in residual kidney function (RKF). This normally entails an initial reduction in sessional frequency from thrice to twice weekly. Not only does this offer “cost benefits for the healthcare service,” the study suggested, but it also “is likely to appeal to the HD popula- tion,” who often prioritise “dialysis-free time” according to the Standardised Outcomes in Nephrology-Haemodialysis (SONG-HD) initiative.

The study was a retrospective meta-analysis of studies, drawing on existing research comparing incremental with traditional implementation, and looking at some 644 records. Its primary endpoint was mortality, while secondary endpoints included “treatment-emergent adverse events, loss of RKF, quality of life and cost effectiveness.”

There was no significant difference in mortality between the groups who experienced traditional or gradual HD implementation. Most studies examined

No significant differences in quality of life emerged. The authors were keen to note that the 44% reduction in individual dialysis sessions performed by participating hospitals compared with traditional implementation resulted in significant cost reduction. They pointed to a study by Vilar et al that indicated incremental HD could cause a more than 20% reduction in costs per patient per year.

There remain questions about incremental HD, the authors stated. The studies they reviewed included “patients [who] did not have fair or equal access to dialysis treatment and were initiated on less frequent HD as a result of financial pressures or a lack of adequate healthcare services.” This may have affected the find- ings, while further limitations included the researchers’ exclusion of studies who did not report on mortality at all, instead only including data points on secondary endpoints. Nevertheless, the authors concluded, the review “lend[s] support to the safety of incremental HD as a treatment for ESKD.”