Did your study findings change your opinion or that of your co-investigators regarding more frequent hemodialysis?
Dr. Hall: Our study results align with those from clinical trials that have been conducted over the past three decades to test the effects of increased dialysis dose (as calculated by urea-kinetic modeling) on important clinical outcomes—namely that dialysis sustains life, but generally does not restore health. In this respect, frequent hemodialysis may improve the lives of some, but is not a cost-effective or practical solution to improving the physical capacity of most patients with end-stage kidney disease.
Would these findings cause you to dissuade proponents of frequent hemodialysis or nocturnal dialysis from advocating for these forms of treatment?
Dr. Hall: Not necessarily, but in terms of physical health it remains uncertain as to who might benefit from more frequent treatments. Frequent hemodialysis may yet improve the physical health of some patients with end-stage kidney disease, for example in those individuals who have little residual kidney function and who struggle with large interdialytic weight gains.
What do you see as the main drawbacks or dangers of frequent hemodialysis or nocturnal dialysis?
Dr. Hall: Overall, relatively few adverse events attributable to the intervention were observed during the trials. Besides the added time commitment, support, and costs associated with more frequent in-center treatments, the primary drawback observed during the trials was that patients randomly assigned to frequent hemodialysis were more likely to undergo interventions related to vascular access than were patients assigned to conventional hemodialysis.
Do these findings have any bearing on peritoneal dialysis?
Dr. Hall: Our study findings have little bearing on the management of patients receiving peritoneal dialysis. These modalities for renal replacement therapy (hemodialysis and peritoneal dialysis) are quite different. In addition, the characteristics of the patients who elect to perform them, at least in the United States, also differ substantially.
That being said, the ADEMEX [Adequacy of Peritoneal Dialysis in Mexico; Journal of the American Society of Nephrology 2002;13:1307-1320; http://jasn.asnjournals.org/content/13/5/1307.full.pdf+html] trial found no significant effects of increasing the dose of peritoneal dialysis on important outcomes such as patient survival and health-related quality of life.
You have stated that we need to do more than manipulate the dose of dialysis to substantially improve or preserve the physical capacity of patients with ESRD. Do you have any such strategies in mind?
Dr. Hall: Indeed. The rising incidence and associated disability of ESRD warrant more attention to the assessment of physical measures and interventions to improve these measures as a part of the routine care of patients requiring dialysis.
In terms of improving physical capacity, several smaller studies have reported favorable changes in muscle strength and composition in subjects on hemodialysis using a combined program of cardiovascular and strengthening exercises. The nephrology community may benefit by evaluating the effects of similar exercise programs on a larger scale.
For many patients on hemodialysis, preservation of these physical parameters may be as important as, if not more important than, marginal increases in longevity with poorer functional capacity.