Question index:
Questions received during this symposium have been paraphrased
and the answers submitted by the speaker are presented.

At what serum creatinine level should one start dialysis?
At what point should a multidisciplinary approach be used?
How should one screen diabetic patients for kidney disease?

Dr. Mendelssohn' answers
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At what serum creatinine level should one start dialysis?
Dr. Mendelssohn:
Unfortunately creatinines are not that accurate a marker. For example, a creatinine of say 500 micromoles/liter in a young, healthy athlete means something very, very different from a creatinine of 500 in an elderly, small, frail woman, for example. But I will try, having said that. We are going to have a problem here with American and Canadian units. I am going to try and John will have to correct me if I mishandle the American units. But a Canadian value of 100 micromoles/liter is an American value of 0.88 mg/dl. We are starting to think about dialysis when creatinine reaches approximately 500 to 600 micromoles/liter. The most recent recommendations suggest that when the creatinine clearance is about 18 ml/min which I think both Canadians and Americans can understand. That is when we are supposed to initiate discussions about dialysis.

If there are any signs of uremia, that is, people being sick, or even if there are any biochemical signs of kidney failure or malnutrition, we are supposed to recommend that dialysis be initiated. When the GFR gets to less than 9 mls/minute, you are supposed to start no matter what, even if you feel perfectly well. So it's 500 or 600. It would be lower than that, for example, in a diabetic perhaps or in a person with heart disease who will not be able to stand the stress of the salt and water. So it is a ball park figure. Now we used to wait for healthy, young people who didn't have diabetes until creatinines were 700 or 800, which would be probably around 6 or 7 in American units. That is the recommendation. The current practice is still lagging behind the recommendations.

Dr. Daugirdas:
Just to clarify. The serum creatinine that you follow is a balance between removal and production. So if you have the same level of kidney function in two patients and one is making twice the amount of creatinine as the other person, the person who is making twice as much creatinine will have a higher level of serum creatinine. It will be double for the same level of renal function.

Creatinine comes from muscle. Muscle mass goes down with age, and it is also a function of your weight. So if you have a 20-year old male athlete, he can have a serum creatinine of 2 mg/dL or approximately 200 micromoles/L and have normal renal function. If you are a little old lady and have very little muscle mass and you have a serum creatinine of 2 or 200, then you renal function can already be moderately impaired.

So it is a bit problematic to judge the level of renal function based on the serum creatinine. Nevertheless, when your serum creatinine begins to be around 4 or 5 mg/dL or 400 or 500 micromoles/L in Canadian units, then you really start thinking about dialysis.

In terms of intervening, in terms of preventing kidney dysfunction, it is very important to intervene early. Most of these interventions, whether they are diet or blood pressure or anemia, work best if they are started early, at a serum creatinine in the range of about 2 mg/dL or even earlier, again depending upon your muscle mass. So if there are those of you out there who have serum creatinines even in the 300 range or high-200s, I still think that that is the time to intervene to try to change you onto the turtle slope instead of being on the hare slope of renal deteriorartion, even if you have an "incurable form of kidney disease" because there is no such thing. I think the new research shows that kidney disease progression sometimes can be halted by some of these measures.

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At what point should a multidisciplinary approach be used?
Dr. Mendelssohn:
No one really knows based upon evidence. There is still a little bit of controversy in the field about whether early referral and a nephrologist's care is just as good as early referral plus the care of the whole team, and it is an important question to answer because the team costs a lot of money. And you wonder if it is worth spending all the money. My personal opinion is that it is well worth the money. The team provides tremendous support to the patients.

The team can include teaching nurses, social workers, dieticians, pharmacists, peer support from patient groups, and they all add tremendous value to the patients. What we try to do is to get the patient transferred to the clinic when we think that dialysis is around a year away. So again, in Canadian units we use a creatinine level of around 300. In American units, that would be around 2.5 or so.

It would be great to get them earlier, but the earlier you get them, the more patients you have. It is like a pyramid. So if you start getting them even earlier than that, the worry is that you would overwhelm the resources of the multidisciplinary team. You would be spending much too much time. So we compromise. We go by about a year. We use a creatinine of around 300, but we also look at the slope. For example, if the slope is steep and we think it is progressing rapidly, we will bring them earlier. Or if we think that a particular patient and family are very needy in terms of support and education, we'll bring them earlier, also.

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How should one screen diabetic patients for kidney disease?
Dr. Mendelssohn:
There are very detailed recommendations that come out of the diabetes associations in Canada and the United States telling family doctors and general internists and pediatricians and endocrinologists how they should be screening diabetic patients for kidney disease. And it is basically checking the urine for microalbuminuria. If microalbuminuria is present, then they should be put on an ACE inhibitor, whether or not they have high blood pressure.

Microalbuminuria is protein in the urine at a level that is not detectible on the routine dip stick that we use. So it is an abnormal amount, above normal but undetectable by the routine dip stick. There are now special dip sticks that can detect microalbuminuria or urine that is sent to the lab if a specific request is made can detect microalbuminuria. We know that if we find it and it persists that it predicts diabetic kidney disease. We know again that we can have a tremendous impact upon this with ACE inhibitor therapy.

The problem is that diabetes is a very, very common problem in our society. This kind of a screening measure has to be taken at the level of the family doctors, the endocrinologists, the pediatricians, etc., and not by the nephrologists. We can't possibly cope with it at that stage. We would be overwhelmed. So the idea is, similar to our Canadian Referral Guidelines, how do you get all of the family doctors in North America, all the internists in North America, all the pediatricians and endocrinologists to actually do it? Because if they would, we could prevent a tremendous amount of end-stage renal disease.

So there are educational activities and continuing medical education events, forums like this that are designed for doctors, Internet teaching that Dr. Daugirdas has been involved in, and it is getting the message out there. Later on in diabetes, there has been some success in some places with multidisciplinary diabetes clinics where the patient can visit and see not just the diabetes specialists, but also the eye doctor and the kidney doctor if they need to, and the dietician, etc., etc. That model of care, again, is great. But it is probably not practical to think that all diabetic patients can ever receive that kind of care given the health care systems in both Canada and the United States.