Sunday, September 18, 2011


The European Association for the Study of Diabetes, have just concluded their annual meeting in Lisbon, Portugal. Amongst, the many interesting paper presented, was one presented by Dr Carl Ostgren ( Lingkoping University, Sweden ) dealing with the issue of a J-curve phenomenon, in diabetic control. Is there a J-curve in Diabetes control ?.
A J-curve phenomenon, is an observation that the better the control of a disease, the better the outcome, up to a certain point. Thereafter, better control, seem to result in more MACE. We have observed this in the control of BP in hypertension. It is well known that when BP control is good, below 130/80mmHg, there is reduction in MACCE. But when diastolic BP lowers below 70 mmHg, there seem to be an increase in MACE especially in patients with a history of CAD. So we are all taught not to lower the BP too much, and also too fast.
Dr Carl Ostgren and colleagues, went through the records of about 33,000 diabetics in the Swedish registry, to analyse HbA1c levels, against registry data of hospital admissions, drug dosages, AMIs, deaths. etc. They also studied the educational levels of their patient cohort.
What they found was that when diabetic control ( using HbA1c levels as a guide ), was between 6-7%, the MACE rates were the lowest. HbA1c levels below 6% and above 7% had higher MACEs, thereby showing that there may be a J-curve phenomenon is diabetic control More intensive control of diabetes, may be associated with more major adverse cardiac events.
Of course, this controversial observation was met wit ( it is reported ) a very heated question time, almost to the point of scolding Dr Ostgren. It is true that observational data is often not confirmatory, and may be more hypothesis generating. Some were calling Dr Ostgren irresponsible to have these reports. Anyway, I believe that as physician scientists, we can see the truth from the facts, and make out our own minds. we must forget that we saw something like this in the large ACCORD syudy, where people rationalised that it was not the level of low HbA1c that was the culprit, but the rapidity at which those levels were reached.
Certainly, like some of my patients, more intensive control means more hypoglycemic episodes. I have a patient ( now 75years ) who insist on insulin and who self increase his insulin dose to achieve a level below 6. He things that he must normalise his blood sugar. No amount of counselling by me and his daughter, will persuade him otherwise. so of course, he has been fainting. I just saw him last week. I hope that he can understand.
To a certain degree, I would agree that there seem to be a J-curve phenomenon is hypertension control and also in Diabetic control
It is only fair to say that the ultimate proof must be large randomised controlled trials, and I do not see any in the horizon.
The controversies continue, and we await more data.

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