Finally the end of KT/V near

[obsidianom]

Kidney Int. 2015 Jun 10. doi: 10.1038/ki.2015.155. [Epub ahead of print]

Once upon a time in dialysis: the last days of Kt/V?

Vanholder R1, Glorieux G1, Eloot S1.

Author information

Abstract

After its proposal as a marker of dialysis adequacy in the eighties of last century, Kt/Vurea helped to improve dialysis efficiency and to standardize the procedure. However, the concept was developed when dialysis was almost uniformly short and was applied thrice weekly with small pore cellulosic dialyzers. Since then dialysis evolved in the direction of many strategic alternatives, such as extended or daily dialysis, large pore high-flux dialysis, and convective strategies. Although still a useful baseline marker, Kt/Vurea no longer properly covers up for most of these modifications so that urea kinetics are hardly if at all representative for those of other solutes with a deleterious effect on morbidity and mortality of uremic patients. This is corroborated in several clinical studies showing a dissociation between removal of urea and that of other uremic toxins. In addition, randomized controlled trials showed no benefit of increasing Kt/Vurea. Finally, this parameter also hardly is evocative for metabolic or intestinal generation of toxins, for their removal by residual renal function and for the complex interaction of dialysis length with removal pattern and patient outcomes. We conclude that apart from being a baseline parameter of dialysis adequacy, Kt/Vurea insufficiently represents all novel strategic changes of modern dialysis. Kt/Vurea is too simple a concept for the complexities of uremia and of today's dialysis.Kidney International advance online publication, 10 June 2015; doi:10.1038/ki.2015.155.


PMID: 26061543  [PubMed - as supplied by publisher] 


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[Rerun]

Good!  I'm constantly getting redraws because my KT/V is off the chart high.  I hope they take it away.

[Jean]

Well, that is really interesting. I know so many people relied on KT/V for a time f fear and that a bad number was life threatening. Hmmmmm

[Vt Big Rig]

Being a relative newbie I have to ask .... if they do away with this what will they use to measure whether we are getting enough treatment. I know presently my nurse is measured on how my Kt/V comes out?

[obsidianom]

Kt/V NEVER measured true adequacy as it only looks at urea which is a NON TOXIC element in the blood . it is not even close to having the dynamics that the real toxins have.  It is a small easy to clean out molecule.   The real toxins are hard to measure now.  so we fooled ourselves by picking urea as it is easy to measure despite being non toxic and not at all like the larger toxic molecules.     Some day there will be a better test.    for now the best way is to look at potassium, phosphorus , fluid removal and how you feel. These are far more important then how much urea you clean out.    Hours on the machine are also important.   10% of total time (about 17 hours per week) is a good starting point as a minimum.

[Vt Big Rig]

Thank you for the information but you have blown my hopes all to heck!! LOL

I presently run a little more than 15 hours a week on Next Stage. My last Kt/V was 3.1. My potassium and phosphorous number are good. And I feel great.

Very hopeful the neph ( and more importantly the nurse because he does what she tells him to  ) lets me go to 4 treatments a week  . I'm Ok with the same hours, if I am gonna get stuck another little while on the machine is worth it to miss a day.

[obsidianom]

Thank you for the information but you have blown my hopes all to heck!! LOL

I presently run a little more than 15 hours a week on Next Stage. My last Kt/V was 3.1. My potassium and phosphorous number are good. And I feel great.

Very hopeful the neph ( and more importantly the nurse because he does what she tells him to  ) lets me go to 4 treatments a week  . I'm Ok with the same hours, if I am gonna get stuck another little while on the machine is worth it to miss a day.

Going to 4 treatments per week will require higher dialysate per treatment and longer time per treatment. The Nxstage on line calculator can give you the numbers.

[Hootie]

How do we get the NxStage calculator? Last time I went there they want medical person credentials. I would like to see what the treatment times and Dialysate amounts would be for my wife when we cannot do 5 days on the NxStage machine. Occasionally, due to scheduling we can only do 4 days. She uses 25 Liters per treatment five days a week. We usually pull about 2.3 on average UF at about 2:30-2:45 hours and a little longer is if the pull number is higher. FF 50.

She feels fine and the KT/V values are typically 2.3-2.6.

[obsidianom]

Some people here figured a way to do it without medical credentials. Go to the Nxstage area on this board and ask. I am a physician so I didn't have that issue. But there is a way to get in . It is a VERY useful tool.

[Vt Big Rig]

Just go into making an account. Make up a number of any kind and say other for type. Got me right in.

Don't change the settings without talking to your neph.

[Zach]

Unfortunately, the end of Kt/V is not as near as one would hope.

Kt/V still useful for measuring dialysis adequacy, according to review
http://www.nephrologynews.com/ktv-is-still-useful-for-measuring-dialysis-adequacy-according-to-review/

“In summary, there are aspects of hemodialysis adequacy in 2015 that clearly extend beyond Kt/V urea; however, the few pieces of hard outcomes evidence that we do have suggest that monitoring small molecular clearance, as measured by Kt/V and its derivative, standard Kt/V, perhaps rescaled to body surface area, remains a useful metric to monitor treatment, especially in the overwhelming majority of patients receiving dialysis on a 3/week schedule,” Daugirdas concludes.

The full review from Kidney International:
http://www.nature.com/ki/journal/vaop/ncurrent/abs/ki2015204a.html

[obsidianom]

I read both articles and find MAJOR discrepancies on both. They were both biased and poor.
In other countries like Australia where they have MUCH better dialysis outcomes then the US , they don't use kt/v and scoff at the US and its use of it.  Just ask DR Agar about it and get him going on the whole issue. Only the US seems to cling to this out dated concept.   I noticed in 1 of the article s the author quoted a study for 1985.  That is really POOR.   I was in medical school in 1985 and SO MUCH has changed since then . I would NEVER use any study from back then in an article .  30 years in medicine is a lifetime.

[Zach]

Here is an interesting take from Japan:

High-quality dialysis: a lesson from the Japanese experience

http://ckj.oxfordjournals.org/content/3/suppl_1/i28.full

"From this therapeutic concept, the patient survival rate is excellent in our facilities: the 1-year survival rate is 91.1% and the 5-year survival rate is 76.6%, although the mean age of our patients is 69 years. We usually adjust the therapeutic modality based on patient complaints, and we call this concept ‘patient-oriented dialysis’ (POD). In the POD system, the prevalence of uraemic pruritus or sleep disturbances was lower than that of the DOPPS. The protein-leaking dialysis modalities with PMMA, EVAL or predilution online HDF form the key concept in the POD system."

and

"Kt/V is one of the most frequently used parameters in determining the adequacy of dialysis because it is simple to calculate and gives some insight into the assessment of dialysis patient survival. Kt/V had consisted of a dialysis dose standardized by body size; however, Kt/V is still dependent on body mass. If we evaluate the adequacy of dialysis only by Kt/V, it would contradict the report that smaller-sized women or elderly patients are easily under-treated [10]. The Dialysis Outcomes and Practice Pattern Study (DOPPS) has not yet clarified the reason why patient survival in Japan has been so excellent, although the mean Kt/V is markedly lower [11]. These issues suggest that high Kt/V does not always lead to increased rates of patient survival and cannot be the golden target of high- quality dialysis."

[dialysisuser82]

Totally disagree with obsidianom about elemination  of Spkt/V! 


I am on dialysis for more than 33 yrs. and I know whenever the Kt/V is down I feel the effect from it.


                Most people say that it is the intellect which makes a great scientist. They are wrong: it is character.
                                                        ----------Albert Einstein-----------

[obsidianom]

You are making some pretty BIG assumptions about this based on erroneous data. First any 1 patient is not a basis for ANYTHING. I base my input on 27 years practicing medicine and the articles I read from respected researchers and practitioners like Dr Agar.   You are 1 patient and your own unique experiences are just that, unique to YOU. When I discuss findings I do it with thousands of patients in mind.
Now to your own findings that when your KT//V is down you feel bad, OF COURSE you do. Kt/V measures UREA clearance mainly. If the machine isn't clearing that YOU GOT TROUBLES as it shows it is not even doing the minimum job.  Urea being a small molecule is EASILY , quickly cleared. If it isn't then you can bet the larger more toxic molecule are not even close to clearing.   Where KT/V is weak is the other end of the spectrum. You can have a high kt/V and still be getting poor dialysis .
Again, you are 1 person as is my wife. In reality neither you nor her matter much in medical science. It takes thousands of patients to really get a statistical measure of what really matters.  In the US where we cling to KT/V , we have horrible statistics on our morbidity and mortality compared with Japan and Zealand.  They do a far better job and don't even check KT/V in Australia /NZ.   
My wifes American trained Nephrologist admitted to me that even though they are forced by medicare to check Kt/v , he realizes it is a very poor indicator of dialysis adequacy.

[obsidianom]

The following was from a study a few years ago looking at dialysate flow rates and clearances and Kt/v.   The part I copied here is relevant to the Kt/v argument.

)." Removal ratios for creatinine and the high-molecular-weight marker, beta(2)-microglobulin, were not affected by increasing Qd from 500 to 800 mL/min. The proportion of patients not achieving adequacy (Kt/V(sp) >/= 1.2) was reduced from 56% at Qd of 300 mL/min to 30% at 500 mL/min and further to 13% at 800 mL/min. It is concluded that increasing Qd from 500 to 800 mL/min is associated with a significant increase in Kt/V. "


Now based on this, we can see that Kt/V increased by increasing dialysate flow from 500 to 800 .   YET REMOVAL OF LARGE MOLOCULE beta 2 macroglobulin was NOT effected. So the supposed increased in adequacy shown by the increased kt/v does NOT HOLD FOR LARGER MOLOCULES . We all know beta 2 macroglobulin is dangerous . As Kt/V rose, there was no change in removal of toxic molecules like beta 2 microglobulin. 
  In the end Kt/v is a FALSE GOD used in the US to "prove " to medicare we are doing the job adaquatly in dialyzing our patients.   Yet it misses the larger more toxic molecules.

[Zach]

Dear Dr. O,

Thank you for those studies.
Could you also provide the links to the studies?
Always good to have the references.

Many thanks,
--Zach

[Zach]

My personal thought on measuring high-quality hemodialysis would include a reduction ratio % of beta-2 microglobulin (B2MRR instead of URR).

[Simon Dog]

I wonder if a two stage filter that combines a standard high flux filter with a lixelle column as standard treatment would reduce B2M amyloidsis.

[obsidianom]

 Dial. 2002 Jan-Feb;15(1):3-7.

Dissociation between dialysis adequacy and Kt/V.

Vanholder R1, DeSmet R, Lesaffer G.
Author information
Abstract

Since the initiation of dialysis, nephrologists have sought an index (or indices) for the adequacy of toxic solute removal. This quest has been characterized by a gradual shift in thinking, ending with a preference for dynamic parameters such as clearances normalized for body size (Kt/V). The threshold Kt/V, however, has changed over the years. While present guidelines suggest 1.2 with single-pool kinetics, higher levels might be proposed in the future. In spite of the known relation between Kt/V and survival, the accuracy of this parameter as a representative of the removal of the whole spectrum of compounds that are responsible for uremia is problematic. Kt/V only assesses the removal of a water-soluble compound from the body water through mostly hydrophilic membranes to the dialysate water. Furthermore, the small size of urea means that convective and/or diffusive transfer through a given semipermeable membrane is unlikely to be representative of larger molecules, especially if dialyzers with a small pore size are applied. Urea kinetics are also poorly representative of the removal of small protein-bound molecules and intracellular solutes with cell membrane-limited clearance. Finally, it should be realized that the Kt/V concept has been developed in a specific population, that is, a group of renal failure patients with few comorbidities, submitted to short intermittent hemodialysis with small-pore bioincompatible membranes very likely using dialysate of lower quality than that used today. Kt/V might well become less accurate and useful in predicting outcomes as different dialysis conditions are pursued, such as dialysis with biocompatible and/or large-pore membranes, (ultra) pure dialysate, alternative time frames, high levels of convection, and/or in populations with a different distribution of body mass.


PMID: 11874581  [PubMed - indexed for MEDLINE]

[obsidianom]

http://www.ncbi.nlm.nih.gov/pubmed/11874581

http://www.ncbi.nlm.nih.gov/pubmed/26061543

http://www.ncbi.nlm.nih.gov/pubmed/10620551

[Zach]

http://www.ncbi.nlm.nih.gov/pubmed/11874581

http://www.ncbi.nlm.nih.gov/pubmed/26061543

http://www.ncbi.nlm.nih.gov/pubmed/10620551

Thank you Dr. Obsidianom!

[Zach]

I wonder if a two stage filter that combines a standard high flux filter with a lixelle column as standard treatment would reduce B2M amyloidsis.

That's exactly what is done in Japan for about 15 years
… and soon to be done in the U.S. on a research-basis.

[dialysisuser82]

You are making some pretty BIG assumptions about this based on erroneous data. First any 1 patient is not a basis for ANYTHING. I base my input on 27 years practicing medicine and the articles I read from respected researchers and practitioners like Dr Agar.   You are 1 patient and your own unique experiences are just that, unique to YOU. When I discuss findings I do it with thousands of patients in mind.
Now to your own findings that when your KT//V is down you feel bad, OF COURSE you do. Kt/V measures UREA clearance mainly. If the machine isn't clearing that YOU GOT TROUBLES as it shows it is not even doing the minimum job.  Urea being a small molecule is EASILY , quickly cleared. If it isn't then you can bet the larger more toxic molecule are not even close to clearing.   Where KT/V is weak is the other end of the spectrum. You can have a high kt/V and still be getting poor dialysis .
Again, you are 1 person as is my wife. In reality neither you nor her matter much in medical science. It takes thousands of patients to really get a statistical measure of what really matters.  In the US where we cling to KT/V , we have horrible statistics on our morbidity and mortality compared with Japan and Zealand.  They do a far better job and don't even check KT/V in Australia /NZ.   
My wifes American trained Nephrologist admitted to me that even though they are forced by medicare to check Kt/v , he realizes it is a very poor indicator of dialysis adequacy.

 Wow that much of educations and a dime for a cup of coffee! 

 What you lack is "Humility".

[iolaire]

I wonder if a two stage filter that combines a standard high flux filter with a lixelle column as standard treatment would reduce B2M amyloidsis.

That's exactly what is done in Japan for about 15 years
… and soon to be done in the U.S. on a research-basis.

The PDF on this post is not downloading for me.