Older Patients, Wiser Care

His blood sugar was above normal. Why did I advise against tighter glucose control?

Last updated:

February 05, 2010
Blood Sugar Test

The case: A diabetic dissatisfied with his blood sugar control

There was no doubt about it: For a man in his early 90s, Mr. T was in great shape. Despite having had type 2 diabetes for 10 years, as well as a heart attack in his 70s, he remained slim, fit, and was still able to drive confidently from his home in Oakland to our clinic in San Francisco.

"I feel good," he told me during a check-up. "I'm hoping to live to be at least 100, like my father. I'm walking 30 minutes every day, just like he did. And I eat healthy foods.

"But I'm worried about my blood sugar," he went on, pulling out his home blood glucose records. "Look. I've been taking my metformin every day, just like I'm supposed to. But the other day, I got all the way up to 182." (Blood sugar in non-diabetics usually measures between 70 and 120.)

I looked over the log he handed me. Then I checked the computer for that day's bloodwork results. Mr. T's glycosylated hemoglobin, also known as hemoglobin A1C, was 7.1 percent, about the same as it had been over the past year.

"Doctor, my son looked on the Internet and read that it's better to have lower blood sugar. Shouldn't I be taking more diabetes medication?"

The challenge: Weighing the pros and cons of tight glucose control

When people develop difficulty naturally regulating the amount of glucose (sugar), in their blood, they're said to have diabetes. Without treatment, diabetics have blood sugar levels that are higher than normal.

People with type 2 diabetes often feel fine if their blood sugar gets only mildly-to-moderately high; they may not even realize they have the disease. But experts always urge diabetics to take this condition very seriously, because over several years higher blood sugar can cause permanent damage to the body, especially to the eyes and the kidneys. Every year thousands of Americans go on dialysis because of kidney damage due to diabetes.

If blood sugar gets up to the moderate-to-very high range, diabetics can also quickly develop such symptoms as increased urination, dehydration, and confusion. And if blood sugar gets really high, consequences can even be life-threatening.

So there's no question that diabetes is a serious chronic medical condition that requires regular medical attention and monitoring.

But experts continue to debate how important it is for a diabetic person to achieve "tight glucose control," which means having one's blood sugar as close to normal as possible. To measure glucose control, doctors often rely on the hemoglobin A1C blood test, since this reflects the average blood sugar level over the previous three months (as opposed to checking a fingerstick glucose, which gives the sugar level at that very moment). A non-diabetic person usually has an A1C between 4 and 5.5 percent. A diabetic person will have a higher result due to higher average blood sugar levels.

For a long time, experts believed that it was best for doctors to work with diabetics to get their A1C as low as possible, through lifestyle changes and/or medication; this often meant adjusting a diabetic's medications until the A1C was less than 7 percent, or even below 6.5 percent.

The trouble is that for many patients, trying to achieve tight control can be burdensome and risky. This is especially true if a patient is taking one of the many types of diabetes medications that can work "too well," and cause blood sugar to fall to dangerously low levels (a situation called hypoglycemia); such patients who are trying to achieve tight blood sugar control usually have to check their blood sugar at least daily, if not throughout the day.

This can require a lot of frail older people (not to mention their caregivers). Frail elders are also more likely to have a catastrophic fall or other serious problem if blood sugar gets low. For this reason, geriatricians don't usually try to get tight control of blood sugar. Instead, we generally focus on avoiding the higher blood sugar levels that can cause short-term complications. We usually aim for a hemoglobin A1C under 8 percent.

Interestingly, in the last few years, scientific research has suggested that very tight glucose control may be linked with a higher risk of death. Supporting this theory, a recently published study of 48,000 type 2 diabetics in the U.K. found that those with an A1C of 7.5 (i.e. moderate glucose control) were less likely to die than those with much lower A1Cs or higher A1Cs.

The solution: Know that moderate blood sugar control is often "reasonable enough."

I applauded Mr. T for wanting to take good care of himself. He'd been diligently checking his fasting blood sugar every morning, and even though most of his numbers were in the 120-150 range, he'd been scared by having occasional higher numbers, like the 182 he'd mentioned. He felt a lot better after I explained to him that it was his hemoglobin A1C test, rather than his blood sugar log, that was most useful for figuring out how well-controlled his diabetes was overall.

I explained how his A1C of 7.1 percent was really pretty good, well below my usual goal of 8 percent. Besides, he was already taking the maximum dose of metformin, a drug doctors like to use because, unlike insulin and many other diabetes drugs, metformin by itself can't cause hypoglycemia. Even if I thought he might benefit from better glucose control, adding another diabetes medicine would up his risk of dangerous hypoglycemia.

After listening to me, Mr. T agreed: There was no need to increase his medications. If he really wanted to bring down his blood sugar levels, he could continue with non-drug strategies, like exercise and dietary management. "I've been eating dessert a few times a week," admitted Mr. T. "But I'd been feeling guilty because my son's been so worried about my diabetes."

I reminded him that although giving up a favorite dessert might lower his blood sugar, scientific evidence hasn't proved that he's likely to benefit from lower blood sugar. And because he was already thin, I didn't recommend weight loss. Besides, I added, there are certain mental benefits in the little pleasures of daily life.

We both smiled.

My prescription for caregivers of people with diabetes:

  • Know the diabetic person's hemoglobin A1C. Doctors usually order this test every 3-6 months. If it's higher than 8 percent, make sure to discuss this with the doctor; a plan to improve diabetes control is probably warranted.
  • Be aware that geriatricians don't usually increase diabetes medications for an A1C less than 8 percent. If the A1C is between 7 percent and 8 percent, and the doctor recommends increasing medication, ask the doctor to explain what benefits he or she is expecting from better glucose control. You should also make sure that non-drug strategies, such as exercise, weight loss, and diet changes, are being used.
  • Understand that short-term complications of high blood sugar are rare when blood sugar is less than 250 mg/dl. Make sure the doctor has told you when to contact him or her regarding higher blood sugar readings.
  • If the diabetic person is on medicines that can cause hypoglycemia, make sure you're familiar with the use of a home glucometer. You should also know the [signs of hypoglycemia] (https://www.caring.com/articles/hypoglycemia-and-diabetes) (low blood sugar) Elderly people are at high risk for falls, confusion, and other complications from hypoglycemia.
  • Know that the conventional target for A1C is 7 percent, but that the burdens of trying to reach this goal probably outweigh the benefits when it comes to the frail, the very old, and those with multiple chronic diseases.