Dr. Brendan Barrett in the Dialysis Unit at the Health Sciences Centre.

A national pilot study on moderately advanced kidney disease and its associated heart and blood vessel problems is being coordinated at Memorial University.

The Canadian Collaborative Group for the Prevention of Renal and Cardiovascular Endpoints Trial (CanPREVENT) involves five centres across Canada, with St. John’s as the coordinating centre. The principal investigator is nephrologist Dr. Brendan Barrett, professor of Medicine at Memorial.

“We wanted to do something significant in nephrology clinical research,” said Dr. Barrett. “Initially we thought we’d be able to do a full-scale trial within Canada, but it became fairly clear that to achieve this might require partnership with sites in the United States.”

Dr. Barrett said the initial idea for an $11 million trial over five years on up to 4,000 kidney patients was scaled back to a two-year pilot study with 500 patients in Canada alone.

“What we’re rolling out this month, which is Kidney Month, is a vanguard pilot study that will be the beginning of a full-scale study,” he said. “The same patients can remain in the full trial and we can enrol others if it looks like we’re meeting our recruitment and other interim study targets.”

While many people think of dialysis as a treatment for kidney disease, Dr. Barrett said that a greater majority of people who have low kidney function actually die of something else, including heart disease.
“Controlling blood pressure and other factors is very important because we know it’s extremely relevant to the way in which kidney and cardiovascular disease gets worse.”

There are many reasons why people get kidney disease, but the growing rate is tied in part to the increase in diabetes. “Over time about one-third of people with diabetes will end up with kidney damage and some will go on to advanced kidney failure. On top of that there is high blood pressure, blood vessel diseases that can affect blood flow to the kidneys, inflammatory kidney diseases and hereditary disorders.”

The pilot study will recruit 100 patients per site in five sites across Canada. “We’re not particularly looking to recruit people known to us with kidney disease,” said Dr. Barrett. “What we’re trying to find out is whether people who have chronic kidney disease of moderate severity can be managed more effectively than currently happens, and for that we need to identify people who don’t necessarily know they’ve got chronic kidney disease, or at lest to include some such people.”

Care for people with kidney disease can range from those who receive no treatment because they don’t know they have a problem, to others who know it and are being treated by their family doctor, through to those who are seeing a specialist. “In recruiting people for this study we will take advantage of electronic health records,” explained Dr. Barrett. “When a person has blood work done, a record is kept at the hospital. Without us knowing who any individual is, we can have the lab prompt the physician who ordered the blood test if the results are within a certain range that are of interest to us. We let the doctor know that he or she can discuss the possibility with the patient of enrolling in the study. This method preserves privacy and confidentiality and it’s the doctor’s choice to let the patient know about the study or not.”

For practical reasons, kidney patients in the Newfoundland part of the study will need to live in the Avalon Peninsula area. “Part of treating kidney patients is to bring their blood pressure down and that may mean seeing them every week or every month. The minimum we need in terms of doing measurements for the study is to see each person in the study every three to four months.”

Dr. Barrett said it is not a trivial matter to measure the intervention being applied in the study. “For example, we’re not using just one drug to lower drug pressure. We’re doing a whole series of interventions including the way the nurse works with the patients, the way the patient gets involved in their own care, the way their family helps them, how the nurse and doctor work together and how they deal with the study protocol.”

The CanPREVENT study will compare usual care with a nurse-coordinated multi-risk factor intervention clinic involving a nephrologist, and applying known treatments to reduce or delay the onset of advanced kidney disease and heart and blood vessel problems such as heart attack, stroke and death. The study will also address issues of costs associated with care and illness.

The pilot study is funded by $1.25 million from the CIHR New Emerging Teams Chronic Disease Management Program, which includes the CIHR Institute for Diabetes and Metabolism, the CIHR Institute of Circulatory Health, the Kidney Foundation of Canada, Heart and Stroke Foundation of Canada, Canadian Diabetes Association and as well $750,000 from the biotechnology company Amgen, $750,000 from Ortho-Biotech and $300,000 from Merck-Frosst Canada.