Screening for type 2 diabetes
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* Kenneth G. Marshall

**[The author responds:]** 

I agree with Wally Shishkov that the most common precipitant of type 2 diabetes is obesity and that it would be a major public health triumph to reverse its ever-increasing prevalence in our society. Shishkov believes that long-term weight loss is achievable for many people. I hope he is right, but evidence published to date does not support this view.1

Alun Edwards objects to my "harsh denial" of the value of controlling glucose, lipids and hypertension in diabetic patients; in fact, I wrote that such patients should be "vigorously treated for all detected risk factors." He also suggests that my statement that "screening will do a great deal of harm" is unsupported, yet I provided numerous supporting references in my article.

Edwards appears to be ambivalent about evidence-based medicine. The phrase "chanting the mantra of evidence-based medicine" in his opening sentence suggests a pejorative view of the subject, yet in his closing sentence he lauds the Canadian Diabetes Association's "careful rating of evidence to support recommendations." If he is in favour of evidence he should know that the Canadian Diabetes Association gave a grade of D to screening for diabetes.2 This grade means that the recommendation is supported by opinion, not randomized clinical trials.

Edwards considers me a nihilist. I think a more accurate description of my attitude would be "snail," as used by Sackett and Holland3 to describe physicians who in uncertain situations avoid interventions that may cause harm. In contrast to "snails," "evangelists" intervene in similar circumstances because it is possible that doing so will prove beneficial. Stephenson4 uses the terms "minimalist" and "maximalist" for these opposing views. Those of the minimalist school believe that patient care must be based on evidence and that the detrimental effects of interventions must be seriously weighed in order to avoid harming patients; those of the maximalist school believe that one should always try to prevent the worst possible eventuality, that interventions are beneficial and that they do not have serious side effects. Both "snails" and "evangelists" want to help their patients, but their ways of doing so follow different paths.

## References

1.  1. Foreyt J, Goodrick K. The ultimate triumph of obesity [editorial]. Lancet 1995;346:134-5.
    
    

2.  2. Meltzer S, Leiter L, Daneman D, Gerstein HC, Lau D, Ludwig S, et al. 1998 clinical practice guidelines for the management of diabetes in Canada. *CMAJ* 1998;159(8 Suppl):S1-S29.
    
    

3.  3. Sackett DL, Holland WW. Controversy in the detection of disease. Lancet 1975;2:357-9.
    
    

4.  4. Stephenson MJ. Gestational diabetes mellitus [editorial]. Can Fam Physician 1993;39:745-8.