Let’s Apply Common Sense to Dialysis: More is Better

Every once in a while, a conference messes up my identification badge and promotes me to MD. Despite working in the nephrology field for 25 years, though, I’m not a clinician of any ilk, but a writer, editor, sometimes researcher, advocate, and close observer. And, the luxury of being out of day-to-day patient care and able to look at the big picture can be useful. At the risk of being simplistic, healthy kidneys work 24/7—yet we replace their continuous, 168-hour a week function with “adequate” treatments of just 10.5 to 12 hours a week. What follows are some points that string together in my head to form a common-sense Gestalt:

1. More hours of hemodialysis = no need for phosphate binders

   High serum phosphate levels predict higher all-cause mortality on dialysis.² Phosphorus is present in both meat and vegetable proteins, and is thus unavoidable, though intake can be reduced. Yet, a metaanalysis found that low-cost, calcium-based binder options raise the risk of blood vessel calcification³—but new classes of phosphate binders can cost hundreds of dollars per month. Dialysis guru John Daugirdas recently observed that 18-30 hours of dialysis are required each week to obviate the need for binders.⁴

2. More hours of hemodialysis control blood pressure without antihypertensives

   This is not a new finding: we’ve known since nocturnal HD studies began to reappear in the early 2000s that slower, gentler, more thorough ultrafiltration conducted over longer hours would naturally reduce blood pressure.⁵

3. Converting from standard in-center HD to nocturnal in-center reduces left ventricular mass

   Even done three times a week in a clinic, longer, slower HD not only protects the heart’s main pumping chamber—it can reverse damage that has already occurred, finds a study by Wald et al.⁶ After a year, 37 patients who converted to in-center nocturnal had a 14.2% reduction in left ventricular mass, along with fewer antihypertensives. (They still needed binders, though.)

4. Pregnant women on dialysis have an 85% chance of a live birth—IF they get 36+ hours of dialysis a week.

   Pregnancy is rare among women who require dialysis, but when it does happen, it can be successful. Michelle Hladunewich and her group⁷ compared pregnancy outcomes in Canada (n=22) with those from the US (n=70), and, as always, the Canadian women fared better. The Canadian pregnancies lasted a median of 36 weeks, vs. just 27 for American women: a tremendous difference in terms of the risks of preterm birth complications and lifelong disability. Intensifying treatment to 36 hours a week or more made it possible for women to have healthy babies.

Maybe it’s just me. But, taken together, these various findings seem to point in a single direction: the human body works better with cleaner blood, cleaner cells, cleaner tissues. People feel better and tend to live longer when their kidney replacement mimics natural kidney function as closely as possible. Carl Kjellstrand, who is an MD and has a PhD made this observation 40 years ago, in 1975,⁸ and he was right. Isn’t it well past time that we update U.S. dialysis practices so more people benefit?