Re: Urban/rural diabetes

The article “Diabetic blood sugar control: An urban/rural comparison” by Gobrial et al. in the December issue [BCMJ 2002;44(10):537] questions whether “suboptimal management of rural diabetics” is in part responsible for the poorer health experienced by those living in northern/rural communities. The authors’ conclusion that “poor health reported for the Cariboo region is not due to inferior management of diabetes” may be true, but their data certainly do not support such a statement.

Rather than strictly confining themselves to a comparison of blood glucose control, the authors extrapolate their results to “diabetes management” in general. This is completely unjustifiable and for many of your readers will simply continue to promote the misconception that diabetes management is all about blood glucose. It emphatically is not. Without even a mention of blood pressure, lipids, smoking, or use of ASA, the authors are totally unjustified in making any comparisons regarding diabetes management.

In diabetes type II, morbidity/mortality is predominantly related to macrovascular disease. The risk of a cardiovascular event is increased up to four times, and the mortality from such an event increased even more so. The risk of an MI in someone with diabetes is similar to that of someone without diabetes who has already had a documented MI.[1] Up to 80% of people with diabetes will die from a cardiovascular event. On account of this very high risk the ADA no longer considers diabetes a cardiovascular “risk factor” but rather a cardiovascular “risk equivalent.”

In terms of “bang for the buck” in reducing morbidity/mortality, it is far better to aggressively treat blood pressure and lipids to CDA recommended goals of <130/80 and LDL <2.5 respectively (for which, incidentally, we have very effective and safe tools), than to wrestle with the frustrations of blood glucose control, for which we have really rather crude tools (which render normoglycemia virtually impossible).[2-5]

This is not to diminish the importance of efforts at optimizing blood glucose control which, though perhaps having a minimal impact on macrovascular events (likely because current tools fail to achieve the strict level of glycemic control necessary to demonstrate a significant impact), have clearly been shown to dramatically reduce the microvascular complications of diabetes.[6,7] The authors’ data on blood glucose management, including from what might be expected to be a centre of excellence (UBC teaching unit) indicate over 75% of patients with an A1C >8 are not on insulin. One wonders why not?

Finally, I must take issue with the authors’ statement that for those over 65 “prevention of diabetes related symptoms becomes the main therapeutic goal.” This is an astonishing comment that flies in the face of CDA guidelines, which clearly indicate age is no barrier to the benefits derived from optimum diabetes management.[8]

—Andrew Farquhar, MD
Kelowna

Dr Thommasen responds

I would like to thank Dr Farquhar for reading the article and I welcome his feedback. I agree that the poor health reported for the Cariboo region is probably not due to inferior management of diabetes, and that the comprehensive management of diabetes also includes management of blood pressure, lipids, smoking, and use of ASA (as well as promoting weight reduction and physical activity). I apologize to people who may have been misled in believing management of diabetics consists solely of monitoring blood sugars and glycosylated hemoglobin levels after reading our article.

The main purpose of our article was to see whether there were significant differences in blood sugar control between urban and rural diabetics; hence the title “Diabetic blood sugar control: An urban/rural comparison.” The finding that there were no significant differences between the practices was reassuring to us, as it meant at least one aspect of diabetes management—monitoring of blood sugar control—was similar between rural and urban physicians. It is also relevant to a comprehensive study we have just completed that attempts to look at all the facets of diabetic management that Dr Farquhar mentions and more (an 11-page quality-of-life survey, glucose and lipids, vital signs, weight, height, ethnicity, sex, age, medical management) for diabetics and non-diabetics living in the Bella Coola valley. This data set will allow us to follow up Dr Farquhar’s recommendation that we also look at management of blood pressure and macrovascular disease in this diabetic patient population.

Dr Farquhar also wonders why less than 25% of patients with elevated A1C values are on insulin in the two practices when the recommendations suggest more people should be on insulin. I don’t know the answer to this question. If there is literature that shows that one can expect rates higher than this, we missed it in our literature review. There are many examples in the medical literature of discrepancies between what the experts recommend and what goes on in the real world—perhaps this is another example of that. My limited experience is that patients still don’t like the idea of needles and physicians don’t like the idea of causing harm (e.g., hypoglycemic attacks are more common with insulin); perhaps that is why insulin recommendations have not caught on.

Lastly, Dr Farquhar wonders about the rationale behind the statement that for those over 65, prevention of diabetes-related symptoms becomes the main therapeutic goal. This statement comes from Berger’s review article, “Rationale for the use of insulin therapy alone as the pharmacological treatment of type 2 diabetes.”[1]

According to Berger, physicians providing insulin to geriatric diabetics do so at their peril because there is a lack of evidence-based medicine studies to support this practice. Berger states that “Before any treatment of type 2 diabetes in accordance with the principles of evidence-based medicine can be generally recommended, the considerable disease heterogeneity must be taken into account, and randomized controlled intervention trials directed to cardiovascular and microangiopathic organ damage end points must be performed for the various subgroups of patients.” He points out that since geriatric patients typically have multiple co-morbidities and the studies to date on type II diabetics are best extrapolated to the younger diabetes type II (e.g., 60 to 65 years of age), one must individualize therapeutic goals. One of these goals is the avoidance of symptomatic side effects of antidiabetic drugs such as insulin.

—Harvey Thommasen, MD
Prince George

References

1. Haffner SM, Lehto S, Ronnemaa T, et al. Mortality from coronary heart disease in subjects with type 2 diabetes and in nondiabetic subjects with and without prior myocardial infarction. N Eng J MED 1998;339:229-234. PubMed Abstract Full Text 
2. UKPDS. Tight blood pressure control and risk of macrovascular and microvascular complications in type 2 diabetes: UKPDS 38. BMJ 1998;317:703-713. PubMed Abstract  Full Text 
3. Yusuf S, Sleight P, Pogue J, et al. Effects of an angiotensin-converting-enzyme inhibitor, ramipril, on cardiovascular events in high-risk patients: The Heart Outcomes Prevention Evaluation Study Investigators. N Engl J Med 2000;342:145-153. PubMed Abstract Full Text 
4. Hansson L, Zanchetti A, Carruthers SG, et al. Effects of intensive blood-pressure lowering and low-dose aspirin in patients with hypertension: Principal results of the Hypertension Optimal Treatment (HOT) randomized trial. HOT Study Group. Lancet 1998;351:1755-1762. PubMed Abstract Full Text 
5. Heart Protection Study Collaborative Group: MRC/BHF Heart Protection Study of cholesterol lowering with simvastatin in 20536 high risk individuals: A randomized placebo controlled trial. Lancet 2002;360:7-22. PubMed Abstract Full Text 
6. The DCCT Research Group. The effect of intensive treatment of diabetes on the development and progression of long term complications in insulin dependent diabetes mellitus. The Diabetes Control and Complications Trial Research Group. N Engl J Med 1993;329:977-986. PubMed Abstract Full Text 
7. Turner RC. The UK Prospective Diabetes Study. A Review. Diabetes Care 1998 (suppl 3);C35-38. PubMed Abstract 
8. Meltzer S. 1998 clinical practice guidelines for the management of diabetes in Canada. Canadian Diabetes Association. CMAJ 1998;159(suppl 8)S1-S29. Abstract Full Text