It is standard in diabetes care to recommend practicing reasonably tight blood glucose control — most people, according to the American Diabetes Association, should aim for an HbA1c level around or below 7%. But when it comes to practicing intensive blood glucose control — aiming for an HbA1c level similar to that of people without diabetes, commonly defined as below 6% — controversy abounds. Several studies have aimed to address the question of whether intensive control yields medical benefits, generally without clear-cut results. Now, another report has been added to the mix.
Earlier this summer, a German research institute — the Institute for Quality and Efficiency in Health Care — released a report that examined existing studies on intensive blood glucose control. Described in a recent article at EndocrineWeb, the report examined seven previously published studies that included nearly 28,000 participants, comparing the effect of intensive control versus standard control on overall death, strokes, fatal and nonfatal heart attacks, kidney disease, eye disease, and amputation. Three of these studies took place after the year 2000; the others took place from the 1960’s to the 1990’s. The groups included in all of the studies were not uniform — some had far more men than women, and vice versa, and some had participants who had already experienced heart problems — making comparison difficult. Nevertheless, the report reached several conclusions.
One conclusion is that in each of the seven studies, there was no reduction in overall death from intensive blood glucose control. In one — the ACCORD trial — the intensive-control group experienced a greater death rate than the regular-control group, leading the premature cancellation of that wing of the study. When the results of all studies were combined, only two significant effects of intensive blood glucose control were found: It increased the incidence of severe hypoglycemia, and reduced the incidence of nonfatal heart attacks. However, these effects were not seen on an equal scale. According to the ADVANCE study (one of the seven), 1,823 people would need to aim for intensive blood glucose control for five years to prevent one nonfatal heart attack; within this group, there would be 23 incidents of severe hypoglycemia. According to the ACCORD trial, 104 people would need to aim for intensive control to prevent one nonfatal heart attack, but there would also be one additional death as a result, along with 7–8 cases of hypoglycemia.
There are several grounds on which the report’s position against intensive control could be disputed. First, the ACCORD trial was somewhat unusual in its finding that intensive control caused a higher risk of death. This means the results could be a fluke resulting from a particular condition of the study — although that condition remains a mystery. It appears unlikely, however, that the actual lowering of blood glucose resulted in a higher risk of death, since participants who died were likely to have a higher HbA1c level than other members of the intensive-control group. Setting this risk aside, it may be reasonable to attempt tight control in people with no history of hypoglycemia, especially if they have an elevated risk of heart attack, and if drugs or other treatment methods with a low risk of hypoglycemia are used. Finally, none of the studies included in the report examined a lifestyle-intensive program to lower blood glucose, relying instead primarily on drugs and insulin.
What do you think — have you tried intensive blood glucose control? If so, how has it worked for you? If not, why not? Are mainstream studies on tight control helpful, or do you agree with those who maintain that the methods used to achieve tight control (drugs, insulin, diet) need to be evaluated separately? Leave a comment below!