How Low Should Your Blood Sugar Go?

Important new guidance for those with type 2 diabetes

From FB: Consumer Reports / Hallie Levine / March 5 2018

People with type 2 diabetes are typically advised to aim for levels of blood sugar, or glucose—the energy from food that fuels our cells and organs—that are close to those for people without diabetes. But just how near-normal these levels should go has long been a matter of disagreement.

Today, after reviewing the current guidelines, the American College of Physicians (ACP) advised that most people with type 2 diabetes not go below 7 percent on the HbA1c test, which measures long-term blood sugar control.

Often, doctors encourage them to strive for an HbA1c of 6.5, which can require high doses of multiple medications. (Normal is less than 5.7, while 5.7 to 6.4 is considered prediabetes—and anything higher is diabetes.) 

But when the ACP analyzed the evidence behind the guidelines, they found that bringing blood sugar levels down to between 7 and 8 was enough to reduce the risks of major diabetes complications such as heart attack, stroke, and damage to eyes, nerves, kidneys, and feet.

“Going lower than that didn’t provide any more benefit, and, in fact, in some cases caused harm by causing blood sugar to drop too low,” explains Jack Ende, M.D., president of the ACP. And left untreated for long enough, low blood sugar, or hypoglycemia, can cause seizures, heart attack, or stroke.

The ACP recommendations are in line with what Consumer Reports and some other organizations have been saying for several years. “It’s much more consistent with what current evidence suggests: Aggressive treatment isn’t just unnecessary for many people but is potentially harmful,” says endocrinologist Marvin M. Lipman, M.D., Consumer Reports’ chief medical adviser.

Not everyone agrees. The American Diabetes Association (ADA), for example, considers an HbA1c of less than 7 percent suitable for the majority of those with type 2 diabetes.

“By lumping ‘most’ people with type 2 diabetes into a 7 percent to 8 percent target range, ACP’s new guidance may cause potential harm to those who may safely benefit from lower evidence-based targets,” says William Cefalu, M.D., chief scientific medical and mission officer at the ADA. 

If you’re currently being treated for type 2 diabetes, here’s what you need to know to make sure that your blood sugar is at the level that’s right for you.

The New Recommendations

To develop its new advice, the ACP reviewed six sets of blood sugar guidelines—from organizations such as the ADA and the American Association of Clinical Endocrinologists—and the evidence behind them. Four of the six recommend a target of 7 percent or lower, and two guidelines suggest a range and advise that doctors take factors such as age and other health issues into consideration.

All the guidelines are based primarily on the findings from five major clinical trials. Some of the trials determined that lowering HbA1c to less than 7 slightly reduced the risk of eye and kidney damage, and others did not.

And, the ACP found, the trials didn’t consistently show that maintaining very low HbA1c numbers helped reduce heart attack, stroke, or deaths overall.

In addition, the evidence suggested that such tight blood sugar control seemed to lead to much higher rates of hypoglycemia—and resulting hospitalizations. 

“Based on our analysis, we felt that the evidence showed that going below 7 percent didn’t reduce deaths or macrovascular complications such as heart attack or stroke, but it did cause harms such as low blood sugar,” Ende says.

In fact, some research found that people who lowered their HbA1c levels to less than 6.5 had a higher risk of death from heart disease than those who were generally between 7 and 8.

The ACCORD study, for example, found that people on intensive drug treatment who got their HbA1c lower than 6 were more than 20 percent more likely to die of any cause, 35 percent more likely to die from heart disease, and almost twice as likely to gain more than 22 pounds.

“When people’s blood sugar gets too low, their body responds as if it’s under major stress: Their heart rate increases and they sweat, both of which increase risk of a cardiac event,” Ende says.

What Should You Do?

The ACP now not only recommends aiming for an HbA1c level of between 7 and 8 percent but also advises that people who dip below 6.5 percent have their diabetes medication doses lowered.

“In these patients it’s reasonable to scale back on dosage and instead encourage them to get their numbers even lower through lifestyle changes such as losing weight and exercising, which carry the same risk-reduction benefits without the potential harm of drugs,” Ende says.

That said, if you have type 2 diabetes, and are younger than 65 and in good health, it’s reasonable to aim for an HbA1c between 6.5 and 7, Lipman says. “And if you’re slightly above the 7 mark—say at 7.1 or 7.2—there’s no reason to push yourself to go any lower. By doing so, you begin to flirt with episodes of low blood sugar,” he says.

If you’re older, and have co-existing health conditions such as heart or lung disease, an HbA1c between 7 and 8 is fine. “In this group, especially if life expectancy is less than a decade, it doesn’t pay to be too strict about it,” Lipman says. That’s because the main purpose of treatment for this group is to prevent symptoms that occur from high blood sugar, such as increased urination, dehydration, and unwanted weight loss, he adds.  

Whether you use diabetes medication or not, it’s important to focus on lifestyle changes—even if your blood sugar is under control.

“Many times, type 2 diabetes can be completely reversed by getting down to a normal weight,” says Michael Hochman, M.D., M.P.H., assistant professor of clinical medicine at the Keck School of Medicine at the University of Southern California and director of the USC Gehr Family Center for Health Systems Science.

One study published in the medical journal The Lancet this past December, for instance, found that about half of people with type 2 diabetes who underwent an intensive weight-management program went into complete remission.

“It’s important for patients to realize that if they are proactive enough about lifestyle, they may not need to be on medication at all,” Hochman says.