Tight control for diabetes may be too low

DEAR DOCTOR K: I have Type 2 diabetes. For years, my doctor emphasized the importance of tight blood sugar control. But I recently read that tight control might not make sense for everyone. Why not?

DEAR READER: It’s a confusing and controversial area. I’ll do my best to put it in context and to explain my own views.

People with Type 2 diabetes have high levels of blood sugar if they don’t take medication that lowers their blood sugar level. Some medicines that successfully lower blood sugar – particularly insulin and sulfonylurea drugs – can be too successful, however: They can drop sugar levels too low.

So the goal in treating diabetes is to lower high blood sugar levels to normal, but not to below normal. Getting the levels down to normal is called “tight control” of blood sugar.

There are two ways of measuring blood sugar. You can measure the sugar level at the moment that you sample the blood, or you can estimate what the average sugar level has been over the past two to three months using a test called hemoglobin A1c (HbA1c). Most doctors urge their diabetic patients to aim for an HbA1c of 7 percent or less. This is considered tight control.

Aiming for tight blood sugar control makes sense for almost all patients when they are first diagnosed with Type 2 diabetes. In large part, that’s because it often can be achieved with diet and exercise alone.

Several studies over the past decade have indicated that using medicines to achieve tight control in older ill patients may lead to worse health than shooting for somewhat less than tight control. Tight control may be too much of a good thing. A more modest goal (targeting an HbA1c level between 7 percent and 8.9 percent, for example) might make more sense.If you are taking insulin or sulfonylurea drugs, particularly if you have several other diseases besides diabetes, talk to your doctor. You might benefit from more frequent home blood sugar testing to detect low blood sugar. If the testing reveals that your blood sugar sometimes gets below normal, maybe it’s better to reduce the dose of medicine a bit.