Saturday, 04 February 2012 21:47

Dialysis: how often and for how long?

Written by  Greg Collette
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I’m still working on the BigD holiday arrangements. It’s slow, but looking good.  More soon.

In the interim, some news about dialysis times.

When I started the BigD in 1995, the standard was to dialyse three times a week for 5 hours per time.  I had known that dialysis was on the cards for me since 1972, when I damaged my left kidney in rough seas in the navy, and then discovered that I had only one (the right was missing in action since birth).

I hung on to my dwindling kidney function (via diet and good management by my nephrologist, John Dawborn) for 23 more years.  But I thought my life was over when I began treatment.  Five hours per time, three times per week was a real pain.  All that lost opportunity to do other things, getting restless and feeling unwell after the fourth hour and losing the rest of the day while I recovered.

Like everyone, I desperately wanted to reduce my hours.  My nephrologist held firm.  He was a great believer in the more dialysis I had, the healthier I would be, and 15 hours per week was his absolute minimum.

I regret to report that a new paper published in Medscape Nephrology on 27 December 2011, backs him up with evidence.  Written by Joel D. Glickman, MD, with the electrifying title Nephrologists Unite: Time to Put the ‘t’ back in Kt/V, it has some really interesting news for us BigD-ers.

What is Kt/V?  It’s a ratio indicating the efficiency of each dialysis session.  Put simply, it uses the speed your blood is pumped through the dialyser, and the length of time it is flowing, versus the amount of blood in your body (calculated by your weight) to estimate when you had have enough dialysis to remove the excess urea.  Completely clean blood throughout your body would be a Kt/V of 1.0, where the amount of blood cleaned equals the amount of blood in your body.  If you want to know more, see Wikipedia here.

But there are a couple of things wrong with using the Kt/V ratio to set dialysis time.

Firstly, kidney failure results in a lot of other toxins besides urea (including the so-called middle molecules).  Most can be removed, but efficiency of removal cannot be measured by Kt/V.

Secondly, for a range of reasons the theoretical 1.0 ratio cannot be achieved.  However many kidney organisations and specialists use Kt/V as an indicator dialysis efficiency.  For example, the US National Kidney Foundation Kt/V target is 1.3.

Unfortunately, over time the idea of this ratio has been reversed to:  “If you achieve a Kt/V of 1.3 over three hours, three times per week then you only need 3 three-hour sessions per week.”  Obviously BigD patients grabbed this news with both hands, because it meant shorter times on the machine.

But some nephrologists (like mine and JD Glickman) were sceptical.  Observational data clearly indicated there were benefits in longer treatment times.  Could this be proven?  Along comes the Glickman paper, with some alarming research stats.  Read the paper for details, but in summary, patients whose dialysis sessions were less than 3 hrs had a 60% increase in mortality. And life expectancy improves dramatically as the length of BigD time increases.

Pretty hard to argue with that: shortening your dialysis time shortens your life.  Or to take the positive view, more time on dialysis, more time on planet earth.

Glickman’s absolute minimum is 4 hrs, three times per week, a total of 12 hours – and longer if you can arrange it.

These findings make John Dawborn look pretty smart.  I have been on 15 hrs per week since I started.  And as I said, I really didn’t like it.

But then, a couple of years later he offered an alternative, which actually meant that we could both be happy.  I moved onto 5 days per week dialysis, with only 3 hours each time.  I have written elsewhere about the benefits of more frequent dialysis (which is also backed up by a steadily growing body of research).

I still dialyse for 15 hours per week.  But I can tolerate it, and I am well most of the time.  I still have things I would rather do, but with some planning, I can often do them while I am dialysing.

So, the bad news is that your BigD session isn’t going to get shorter any time soon.  The good news is (1) that you will live longer (for some people it will just feel longer), and (2) there is a way around those long hours and the roller coaster of three times a week.

Maybe it’s time you revisited how long and how often you dialyse?



Greg Collette

Greg Collette

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