Montreal, Canada, June 28, 2001 - Data presented from the largest randomized controlled clinical trial ever completed in dialysis patients suggest that peritoneal dialysis (PD), a flexible home-based dialysis treatment for people with chronic kidney failure, might have far broader applicability than current practice patterns suggest. This study, led by researchers in Mexico and conducted under the auspices of the Mexican healthcare authorities , and supported by Baxter Healthcare Corporation and its Mexico affiliate, was presented this week at an invited scientific session at the IX Congress of the International Society for Peritoneal Dialysis (ISPD) in Montreal.
According to Peter G. Blake, M.D., associate professor of medicine at the University of Western Ontario, Canada, and member of the National Kidney Foundation Dialysis Outcomes Quality Initiative (DOQI) Peritoneal Dialysis Adequacy Workgroup, "This is a pivotal study for the nephrology community worldwide because it is a high quality, multi-center, prospective, randomized, controlled trial with a large number of patients, which gives us highly credible results. The study provides us with statistically sound evidence for simplifying our PD treatment practices-without sacrificing patient outcomes. The findings, which challenge existing treatment recommendations for peritoneal dialysis, should make it significantly easier for physicians to prescribe peritoneal dialysis and may also make it possible for many more patients to benefit from the therapy."
Declining kidney function results in higher levels of toxins and waste products in the blood. When the kidneys no longer adequately eliminate toxins from the bloodstream, peritoneal dialysis helps to clear these unwanted substances through the peritoneal membrane, commonly measured in terms of small solute clearances like urea and creatinine. This membrane, located in the abdominal region, serves as the therapy's natural waste filter and is a substitute for the role healthy kidneys play in waste product and toxin removal.
Until now, many kidney specialists prescribing peritoneal dialysis have believed that increasing small solute clearances would result in better survival. Increasing small solute clearances can be achieved either by filling higher volumes of fluid into a patient's abdominal cavity or by performing more patient exchanges of fluid each day, which has often been difficult for patients, physicians, and nurses to achieve. This practice, in turn, has resulted in increased treatment cost, generally more complex prescription management, and may also be a contributing factor to higher rates of patient withdrawals from therapy due to an inability to achieve defined target clearances.
The new evidence presented at ISPD allows for a better understanding of PD therapy-particularly the relationship between the amount of clearance achieved and patient survival. In everyday clinical practice, many patients have difficulty achieving the high levels of small solute clearance that have become the clinical standard in many parts of the world (60 liters per week of creatinine clearance). This study provides the first evidence showing that pressing for higher levels of small solute clearance-which is difficult for so many patients-yields no difference in patient survival compared with the ranges of clearance more easily achieved during real-world practice. The findings suggest that many patients may have unnecessarily stopped PD therapy as a result of the assumption that the lower levels of clearance would compromise patient survival.
"Although the full global implications of this study still need to be assessed, my colleagues and I now have reassurance that we can prescribe a range of prescriptions tailored to our patients' individual needs while achieving the same survival benefit. We thought this survival benefit could only be achieved by pushing aggressively towards a single target clearance level, which was often overly demanding on our patients," said Dr. Blake.
"I look forward to peer review and publication of this study so that organizations that produce treatment guidelines can reassess current standards."
Clinical Trial Mirrors Real-World Clinical Practice
The ADEMEX (Adequacy of Peritoneal Dialysis in Mexico) study is a prospective randomized controlled trial of 965 continuous ambulatory peritoneal dialysis patients in Mexico who were followed for a minimum of two years. This landmark trial was designed to test the hypothesis that increasing the removal of certain toxins could reduce patient mortality, the primary endpoint of the study. Patients were randomized to two study groups: the active control group was prescribed a standard 2L exchange four times a day, which is the usual prescription used in Mexico in non-study patients (average peritoneal creatinine clearance of 45L per week). The treatment group was prescribed a modified dose by increasing fill volume (to 2.5 or 3L) or by increasing the number of exchanges to 5 daily with 2.5L to achieve a prescription target clearance of 60L per week.
Patients enrolled in the study were randomly assigned to the treatment or the control groups. At baseline, the study groups were equivalent with respect to demographic characteristics (age and gender), etiology of renal disease and prevalence of co-existing conditions (e.g., diabetes), as well as blood tests and physical examination measures (e.g., blood pressure, weight, height).
The clinical study design was successful in achieving the intended separation in peritoneal creatinine clearance measurements, which were higher in the intervention group, and in sustaining this separation throughout the course of the study. On average, the two groups were separated by a highly significant difference of 11 liters of creatinine clearance with no difference in survival between the two groups. In addition, significant separation was also achieved between the two groups relative to urea Kt/V, another measure of small solute clearance (control group peritoneal Kt/V averaged 1.62 vs. 2.13 for the treatment group), with no resulting difference in survival rates.
Treatment Options for People with Kidney Disease
Two treatment options are available to patients with chronic kidney failure: transplantation and dialysis (hemodialysis or peritoneal). Peritoneal dialysis, which is a form of dialysis performed in a patient's home, uses the peritoneal membrane as the filter device. To gain access, a catheter is surgically inserted through the wall of the peritoneal cavity into which the dialysis solution is infused.
Through the process of osmosis, toxins and excess fluids move across the membrane into the solution. After a predetermined dwell period, the solution is drained from the cavity through the catheter. The other form of therapy is called hemodialysis, which removes waste products from the blood accessed through a needle inserted into a blood vessel in the arm or leg. The blood is then pumped through an artificial kidney machine containing a filtering system called a dialyzer that cleanses the blood and returns the cleansed blood back to the body. Most people undergoing hemodialysis visit a hospital or dialysis center three times a week for a several hour dialysis session.
It is estimated that more than one million people worldwide suffering from chronic kidney failure are treated with some form of dialysis therapy, 10 to 15 percent of whom use peritoneal dialysis. It is expected that the number of people with chronic kidney failure will grow worldwide by eight percent a year.
Baxter is a leading provider of renal products and services worldwide. In 1956, the company pioneered hemodialysis with the introduction of the first widely available artificial kidney machine. Nearly 20 years later, Baxter was one of the first companies to introduce PD.
Baxter Healthcare Corporation is a wholly-owned subsidiary of Baxter International Inc., a global medical products and services company that, through its subsidiaries, provides critical therapies for people with life-threatening conditions. Baxter's products and services in bioscience (biopharmaceuticals, vaccines, biosurgery products and transfusion therapies), medication delivery and renal therapy are used by health-care providers and their patients in more than 100 countries.
Media Contacts: Sally Benjamin Young, 847-948-2304
Stephanie Lazor, for Baxter, 212-213-7265
Investor Relations
Contacts: Neville Jeharajah, 847-948-2875
Mary Kay Ladone, 847-948-3371
--Study Presented During IX Congress of the International Society for Peritoneal Dialysis
--More Patients May Now Benefit From this Home-Based Dialysis Therapy