What Is the Best Way to Treat Diabetes?

Medical controversies last a long time and are often bitter not only because science gives provisional rather then definitive answers to most questions, any of which answers may soon be overturned by further evidence, but because science by itself provides no means of deciding between incommensurable results according to a single criterion of value. Besides, everyone likes a good intellectual argument and wants to keep it going as long as possible.

An editorial in a recent edition of the New England Journal of Medicine claims that the long-running controversy over whether surgery or angioplasty is better for diabetic patients with ischaemic heart disease has now been decisively resolved in favor of the former, thanks to a paper published in the same edition. The matter is not a small one: in the United States alone 175,000 diabetic patients were treated last year either with surgery or angioplasty, and the figure is likely to rise as the number of diabetics grows.

The paper described a trial in which 947 diabetic patients with ischaemic heart disease underwent surgery and 953 underwent angioplasty (there were no untreated controls). At five years, mortality in the angiolasty group was 16.3 percent as against 10.9 percent in the surgical group; in total 26.6 percent of those treated with angioplasty had either died or had had a stroke or heart attack, as against 18.7 percent of the surgical group.

You might think, as the writer of the editorial evidently thinks, that the matter is now settled once and for all: surgery is best. But I noticed something implicit in the figures to which the authors did not fully draw attention. Patients who underwent surgery were twice as likely to have strokes as people who had angioplasty, and furthermore the strokes that they had were twice as likely to be incapacitating as those suffered by the angioplasty group. If my arithmetic serves me (which it may not), there were about 10 more patients in the surgery group with incapacitating strokes than in the angioplasty group. On the other hand, about 50 lives would have been saved by the surgery by comparison with angioplasty.

How does one compare the worth of five lives saved at the cost of one incapacitating stroke? To make an informed decision, a patient must know both the absolute and relative risks of good and bad outcomes of the procedure to which he is giving consent, and to make that decision at a time when he is probably not feeling at his best. Even the doctor advising him may not have all the evidence at his fingertips, or understand its meaning: such a thing has been known. Besides, according to the new medical ethics, the doctor is no longer an adviser, which is paternalist and therefore bad: he simply lays the scientific evidence before the patient in as neutral and objective a fashion as possible, and lets the patient decide. Perhaps diabetic patients with ischaemic heart disease will have to be given a copy of this paper. I wish them luck.

There is one more question to which the paper does not address itself, but is not without a certain importance. Many or most of the patients treated were approaching the age when their cognitive reserve had shrunk. Surgery is often associated with an irreversible decline in cognitive functioning, sometimes a very marked one. If, then, there were a difference in outcome between the procedures from the point of view of the patient’s cognitive capacity afterwards, it would be important for him to know it: that is, if Man is a rational animal and mere survival not his highest good.

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Images courtesy shutterstock / mayamaya / Miriam Doerr

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