There's a vigorus debate?

While reading the Congressional testimony around the great EPO kerfluffle I came across the American Association of Kidney Patients Written Testimony to the House Ways and Means Committee Regarding Patient Safety and Quality Issues in End Stage Renal Disease Treatment, submitted on 12/05/06.

Most of it is the sort of milquetoast equivocation that I am use to seeing but one paragraph really caught my eye:

Moreover, in the kidney community today, there is a vigorous debate about the adequacy of medical care of dialysis patients, prompted by apparently higher U.S. dialysis patient disability, morbidity, and mortality in cross-national studies. Some have argued that it is a “national disgrace that the death rate now solidly stays in the region of 24% every year and has more than doubled over the last 30 years” (Kjellstrand, CM, Blagg, CR, “Differences in dialysis practice are the main reasons for the high mortality rate in the United States compared to Japan,” Hemodial Int. 2003; 7(1): 70). Others believe that cross-national comparisons are flawed for selection reasons (i.e., sicker, older patients are denied dialysis in comparison countries) and that the U.S. should take pride in the unique availability of dialysis here (see, e.g., Friedman, EA, “International comparisons of survival on dialysis: Are they reliable?” Hemodial Int. 2003; 7(1):59-66). In any case, with the U.S. ranking last among industrialized countries in mortality for kidney patients, there is a clear need to take a close look at the adequacy of medical care for U.S. dialysis patients.

Come on. The statement that “cross-national comparisons are flawed for selection reasons (i.e., sicker, older patients are denied dialysis in comparison countries) and that the U.S. should take pride in the unique availability of dialysis here” is unsupported. Dialysis is not uniquely available in the US and in any case those cross-national comparisons are apples to apples. The convincing studies illustrating the US ESRD disgrace are case mix adjusted.

When that 2003 article by Friedman came out the data was slightly gray but in the last three years Blagg’s contention has been proven “Differences in dialysis practice are the main reasons for the high mortality rate in the United States compared to Japan”. Let’s put the “comparisons are flawed” canard to rest once and for all.

You are absolutely right, my friend. The MANY papers that have come out of the DOPPS study, which is an international (12-nation) comparison of dialysis practice patterns demonstrates that differences in mortality rates between countries are not due to differences in case mix (these are adjusted for), but rather to differences in practice.

My personal prejudice is that the root cause of the mortality differences is treatment time–the “elephant in the room”, at least IMHO. Treatment time is not routinely collected in the USRDS, though it is captured in the ESRD Network CPM report, thankfully. In Europe and Japan, average treatment times (for 3x/week in-center HD) are significantly longer than they are in the US. One DOPPS paper found that HD treatments less than 3.5 hours are associated with a 33% increase in the relative risk of death. Another, recent DOPPS article in April, '06 Kidney International found that every extra 30 minutes of treatment reduces the relative risk of death by 7%.

A number of other factors have been found to be important, including:
Serum albumin level greater than 4.0 g/dL - Of course, with longer treatments, people are better-dialyzed and less protein-averse, so they may eat better and run less risk of malnutrition. It’s also possible, though, that more exposure to the dialysis circuit might lead to more inflammation, which could offset that benefit. Still, there’s no question that poor dialysis and uremia cause people to lose their appetites, especially for protein.
Hemoglobin greater than 11 g/dL - When the blood is cleaner, e.g., with nocturnal hemo (8 hours at night), RBCs may live longer. Some studies have found that less EPO is needed, others have found this effect cancelled out by the increased blood loss or damage to blood cells, perhaps from greater exposure of blood to the blood pump.
Interdialytic weight gain - More fluid is removed during longer treatments, and the interdialytic interval is also less. Since longeror more frequent treatments tend to cause fewer interdialytic symptoms, sodium modeling (which causes thirst after treatment by causing sodium-loaded) may not be needed.
Bone mineral metabolism - Reports of nocturnal home hemo have typically found that instead of needing phosphate binders, people who use this treatment need phosphate supplements. Removal of phosphorus (which “hides” inside cells and between cells) and other small, middle and large molecules is a function of time, not just dialyzer clearance.
Use of a fistula - I heard Dr. Twardowski present at the Annual Dialysis Conference last year, and he noted that in Europe and Japan (where treatments are typically longer), blood flow rates are much slower. In the US, it’s typical to run at bfrs of 450 or 500, so a fistula has to be able to stand up to that. In Europe and Japan, bfrs of 250 or 300 are much more common, so a fistula that would never be viable in the US is fine there.

For in-center HD, increasing treatment time means hiring more staff and running centers later into the evening. With Medicare payments that don’t cover costs, this simply isn’t going to happen–where would the incentive be to do this? The best way to get longer and/or more frequent treatments is to do them at home.

Dori is there anyway to pair time on the machine with the dialyzor’s weight when doing the analysis? I would bet a nickel that the US has the lowest treatment length per kilogram.

Good question–I have no idea. Maybe the DOPPS folks could answer that, I’ll ask them.