Major Outcomes With Personalized Dialysate TEMPerature

Overview

People with failed kidneys need an artificial kidney machine (called dialysis) to remove toxins and extra fluid from the body. Most patients receive dialysis treatments at a hospital three times a week. During treatment, a patient's blood pressure may drop, causing dizziness and muscle cramping. Repeated drops in blood pressure can also injure the heart and brain. Over time, this can lead to heart attacks, strokes, and sometimes death due to cardiovascular causes. New research shows that cooling the temperature of the dialysis fluid (called dialysate) can reduce heart and brain injury. In most hospitals, all patients' dialysate temperature is set at 36.5 ºC (to match body temperature). In a study of 73 patients, we showed that reducing the dialysate temperature by 0.5 ºC below body temperature protected the heart and brain from injury \[1,2\]. We now want to test this simple, safe, low-cost intervention in a large study with \~7500 dialysis patients in Ontario. We can lower the dialysate temperature on dialysis machines in Ontario at no added cost. This intervention has the potential to reduce many hospitalizations and deaths in Ontario, and relieve suffering in patients with kidney failure.

1. Statement of the health problem or issue Dialysis is a life-saving treatment for patients with kidney failure. However, over 20% of patients die within one year of starting dialysis from heart disease or stroke. One reason that so many dialysis patients die from heart diseases and strokes may be related to the dialysis treatment itself. During dialysis, blood pressure often drops, and the flow of blood and oxygen to the heart and brain is reduced. Over time, this can cause significant damage to vital organs and result in heart attacks, strokes, and even death due to cardiovascular-related causes. Our team was the first to show that the heart and brain become starved of blood and oxygen during dialysis. We and others have shown that lowering the temperature of dialysis (to just below the patient's own body temperature) improves blood flow and protects the heart and brain during dialysis. We will now determine if this method can prevent heart attacks and strokes in a large population of dialysis patients. 2. Objective of your project The purpose of this study is to test the effect of outpatient hemodialysis centers randomized to (1) a personalized temperature-reduced dialysate protocol or (2) a standard-temperature dialysate protocol for 4 years on cardiovascular-related death and hospitalizations. 3. How will you undertake your work? We will conduct a cluster randomized controlled trial. Our study will include \~7500 dialysis patients in 84 dialysis centres across Ontario. The name of this study is MyTEMP. Patients in 42 of the 84 dialysis centres will be in the treatment group and they will receive personalized dialysis (0.5-0.9ºC below their measured body temperature). Patients in the other 42 centres will be in the control group and will receive standard dialysis at a fixed temperature of 36.5ºC. This study will last for four years. At the end of four years, we will compare the rate of cardiovascular-related deaths, heart attacks, strokes, and heart failure in the treatment and control groups. 4. What is unique/innovative about your project? We usually need to study a large number of patients in a clinical trial to reliably understand the effects of treatment. Normally, a study with 7500 patients would cost more than $15 million dollars to conduct; however, our study will provide a reliable answer to the question being asked and cost less than $2 million. This is because we will use data that is already being collected by our healthcare system. For example, when a patient is hospitalized for a heart attack or stroke, this information is recorded in a secure healthcare database. We will be able to analyze these healthcare data at the end of the study (and link patient outcomes to the type of dialysis treatment received (i.e. treatment or control)). This innovative study design means that our study will be much larger (but cost much less) than a traditional clinical trial. This pragmatic trial includes all patients who receive chronic in-centre hemodialysis patients in participating Ontario centres. High-risk patients with multiple comorbidities, including cognitive impairments or disabilities, who are often excluded from trials because of their high-risk status are eligible for participation in the MyTEMP trial. By including patients from a variety of medical, ethnic, geographic, and socioeconomic backgrounds, the results of our trial should be broadly generalizable. 5. What is the impact of the proposed research? Currently, many patients worldwide receive hemodialysis with a dialysate temperature of 36.5ºC to 37.0ºC. Lowering the dialysate temperature below a core body temperature is a promising intervention that has the potential to reduce the risk of cardiovascular-related mortality and major adverse cardiovascular events in patients on hemodialysis. At four years of follow-up, our trial is powered to detect a minimum 20% hazard rate difference in the composite outcome of time to first cardiovascular-related mortality or hospitalization for major cardiovascular events among centres that use a temperature-reduced personalized hemodialysis protocol compared with centres that use a standard-temperature hemodialysis protocol.