Haemodialysis for French diabetic patients

Guy Laurent, Edouard Calemard and Bernard Charra

Centre de Rein Artificiel de Tassin, Tassin, France

Sir,

In the January issue of Nephrology Dialysis Transplantation (Nephrol Dial Transplant 1999; 14: 30–31), Eli Friedman points at the issue of haemodialysis treatment in patients with diabetes mellitus (DM) referring specially to our country and to our unit.

Based on a 15-year-old report, Friedman suggests that the `miraculous longevity' we reported was essentially due to a patient selection bias getting rid of diabetic patients, while those who `were not accepted for dialytic therapy' were left to die. Even taking into account the provocative and stimulant tone Friedman has accustomed us to, we think his paper needs some comments.

We must first point out the fact that in the same 1983 EDTA meeting report, the European Registry incidence rate of DM was reported to be increasing from 2 to 7%, and Vicenzo Cambi (making the case for short dialysis in contrast to long dialysis pleaded for by Guy Laurent in the same guest lecture) reported 3.5% of diabetic patients in his own population. We have never pretended that the Tassin population was representative of the ESRD population `at large', but in 1983 European data on DM incidence and prevalence appeared homogeneous, Tassin was not an exception.

Second, we do not contest that the proportion of diabetic patients in our 1983 study, as generally in Europe, was lower than that observed in the United States at the same epoch. Was this lower proportion of diabetic patients due to a higher mortality of diabetics before the stage of end-stage renal disease or to a low referral rate by diabetologists and GP, is another question we cannot answer. We contest though that there was any deliberate dialysis access restriction in Tassin, as in France, or in most European countries at that time. Patients referred for dialysis were accepted, be they diabetic or not.

Third, the topic of the paper Friedman refers to was the clinical outcomes of short vs long dialysis as a function of treatment method per se, not an exhaustive analysis of dialysis clinical outcome factors.

The situation has changed in Tassin as everywhere else since 1983; the incident population of diabetic patients has crept up in 1998 from 4 to 36%. We have indeed published many papers reporting this change in demography and comorbidity. Of course the crude mortality has in the same time increased drastically: the 5-year survival dropped from 89 to 51%. On the other hand the standardized mortality ratio, which takes into account patient age, race, sex and cause of CRF, remained quite stable over the last 10 years in Tassin: about 50% of the expected US mortality according to the USRDS standard mortality tables. This shows that when adjusting for patients characteristics (although co-morbid factors are presently not included in the SMR method) the dialysis method used has a critical relevance for the clinical issue.

That both patient case-mix and treatment quality do influence the issue can hardly be debated. Even if the addition of other risk factors (and DM is obviously one of them) confuses its evidence, treatment quality remains a critical factor which deserves all medical motivation and action. By quality we mean not only the urea Kt/V but other factors such as session duration, nutrition, and of course volume overload and blood pressure control. The diabetic patient population will, more than any other, benefit from a high quality dialysis treatment, and, due to its cardiovascular instability, needs a very smooth, slow dialysis.

We think that it is not scientifically fair or productive to use 15-year-old data to transform the very concerning problem of diabetic end-stage renal failure treatment into a polemical debate. The best method for ensuring superior survival is not `to treat patients less likely to die', as stated by Friedman, but to treat them better.


 

Reply

Eli A. Friedman

Division of Renal Disease, State University of New York, Health Science Center at Brooklyn, USA

Sir,

Laurent, Calemard and Charra have my respect and admiration for championing the benefits of longer dialysis. There is no doubt that their work stands as a model for others to emulate. Our disagreement centres about the now mythical yet erroneous comparisons of mortality during end-stage renal disease (ESRD) therapy in Europe and the United States.

To grasp the difference in perspective on both sides of the Atlantic, note that as Tassin approached the US proportion of incident diabetic patients, the `crude mortality' at 5 years crashed survival from 89 to 51%. Still Laurent, Calemard and Charra speak of their death rate as `about 50% of the expected US mortality'. But, is this so? Are we again dealing with spurious unfair comparisons to make European outcome look better? I think that shielding national statistics by noting that `Patients referred for dialysis were accepted, diabetics or not', like a Bikini swimsuit reveals a lot while hiding the most important part. In my commentary, I was not discussing how patients did or did not get to nephrologists, my interest was in how thoroughly health systems responded to the need for ESRD care. It seems to me that in comparison to the US, many French patients with ESRD die untreated. What is the basis for such an assertion?

After being scolded for being `not scientifically fair or productive' by using `15-year-old data', I represent the issue relying on the most up-to-date source. In 1997, according to the US Renal Data System for 1999, the incident rate for ESRD treatment in France was 123 per million while in the US it was 296 per million. I can think of only three explanations for such disparity: (i) ESRD is only 42% as common in France as in the US; (ii) the US treats double the number of patients because of inclusion of `inappropriate patients' due to bias, financial greed, or other bad judgment; (iii) France treats less than half the number of patients because of a system that is inadequate to meet the need whether by non-referral or other sequestering of patients.

What I am really attempting to get across is that when France and the rest of industrialized Europe wish to criticize (overtly or by celebrating `local' statistics) survival on dialysis in the US, patient groups must be equivalent. It is not enough to `adjust for patients' characteristics'. I can only guess what the 1-, 5- and 10-year survival in France might be for an intake group of typical US ESRD patients whose mean age is 61.1 years, of whom 43% have diabetes, and 51% are age 65 or older while 23% are age 75 or older. In summary, I am fully able to recognize the marvelous accomplishments of the Tassin group without being convinced that Tassin, France, Europe, or any other geographic region proffers better survival for all of the population under its aegis given the condition that everyone must be treated.





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