Why the 'Kt/V deception' is a good start for India
Posted Jan 03 2012 9:32pm
Dr. Peter Laird, in a great post at his blog, " HemoDoc, From Doctor to Patient ", says "Each month, dialysis patients anxiously await the results of blood tests. Each month, the renal staff and physicians pronounce their dialysis adequate by a magical wand without dimensions called the Kt/V. Yet, each month, these same patients die at a rate 2.5 times that of patients undergoing chronic hemodialysis in Japan."
Entirely true Dr. Laird. This is entirely true for the United States and countries that are using at least Kt/V to determine adequacy. The main argument against Kt/V is that it uses urea as the molecule to determine clearance and from this, the measure of adequacy.
While urea is one of the molecules being removed by dialysis, it is by no means, a representative molecule that actually determines that the dialysis is adequate. There are a number of other molecules that dialysis removes and which have a different rate of removal than urea. Urea is a much smaller molecule than many other molecules that are being removed and is therefore, removed much more easily than these other molecules. So, to assume that if you've removed enough urea, you have had adequate dialysis is to be too optimistic since dialysis is actually much more than removing only urea.
There are a number of other measures that have been suggested by a number of different experts. Many of them are much better than Kt/V to determine adequacy. These are all excellent alternatives to Kt/V. Not for India however.
Let me explain.
Most of these indices require a host of blood tests to be done every month or every six weeks. Take Dr. John Agar's Good Dialysis Index . It is one of the best that I have seen among the newer adequacy measures. However, it needs the Serum Iron, Transferrin Saturation, Serum Calcium, Serum Phosphorus, Serum PTH Intact, Albumin and C Reactive Protein to be checked every six weeks.
Yes, I can almost hear all Indian readers of this post laugh out loud!
Many patients resist any blood tests to be done every month. Some will agree, but only after a howl of protest. I don't blame them. Most countries that get these kinds of blood tests done are from countries where the patients do not have to pay for them out of pocket. So, they would hardly have a problem with that. In India, where costs are the biggest problem since most patients pay out of pocket, how can we expect patients to get the battery of tests required to be able to calculate these indices?
Coming back to Kt/V. Yes, it is a flawed measure. But it is a measure nevertheless. In fact what the experts ask us to do (including Dr. John Agar) is to not rely only on the Kt/V. But they would never say do not measure the Kt/V.
When I joined the dialysis industry as a professional and started looking at dialysis from the blunt side of the needle rather than the sharp side I was used to all these years, I found a shockingly great apathy for adequacy. No one did Kt/V! It was mostly some theoretical concept in the text books. Of course, the industry had a reasonable argument to back this. Patients did not want to do tests. Patients did not want to increase their monthly financial burden.
But a start must be made somewhere. We need to move towards adequate dialysis for patients. To be able to do that we must, first of all, know for sure, what kind of dialysis they are getting. I find that Kt/V is a good start. Gradually we must combine it with other measures to come up with our own index. But Kt/V must be measured. It will at least tell us those patients in whom even the urea is not being adequately removed and I suspect that there must be quite a bunch.