Worse, targeting low blood sugar levels can cause harm. In one instance, investigators actually had to stop a trial early because patients who were targeting hemoglobin A1C levels of six or below had significantly higher rates of death than patients targeting levels in the sevens. We don’t know exactly why this happened. What we do know is that aiming for levels below seven increases the risk for “hypoglycemia,” or low blood sugar reactions. Severe reactions can result in confusion, coma, falls, fractures, abnormal heart rhythms and even death.

Older people are especially susceptible to severe hypoglycemia. With age, kidneys become less efficient, which causes insulin (or other drugs) to accumulate in the body; this, in turn, can lead to hypoglycemia. What’s more, older people often take multiple medications, some of which may interact with diabetes drugs. This, too, may cause hypoglycemia. Using multiple medications or complex insulin regimens also increases the chances of errors, such as taking the wrong dose or the wrong type of insulin. Finally, older people have fewer warning symptoms when they experience mild dips in blood sugar, and this leaves less time for them to react and treat the problem before it becomes severe. This is precisely what happened to my patient.

Given the questionable benefits and the very real risks of going below seven, the American Geriatrics Society and the Veterans Affairs diabetes guidelines have, for years, recommended a cautious, case-by-case approach for older patients. For those with serious health problems, or prior history of hypoglycemia, going below seven may not be worth the risks involved. The problem is that we haven’t put these guidelines into practice.

In a new study published today in JAMA Internal Medicine, my colleagues and I used nationally representative data from 2001 to 2010 and showed that 62 percent of adults over age 65 went below seven. But here’s the catch. We found absolutely no difference in how people were treated based on their health. In other words, patients in poor health and at risk for hypoglycemia tended to be treated as aggressively as far healthier patients. This seems to confirm that we have been adhering to a one-size-fits-all approach, despite the risks that it poses to millions of older Americans.

Part of the problem is that there are strong incentives in place to keep the status quo. The diabetes drug industry has a vested interest in selling its products to as many Americans as it can, and has been incredibly successful at doing so. Sales of diabetes drugs in 2013 were about equal to the combined revenue of the National Football League, Major League Baseball and the National Basketball Association. There is nothing wrong with the industry selling its drugs, but it is the job of the medical profession to guide what treatment patients receive. To do this properly, doctors with financial ties to diabetes drug industry shouldn’t be writing guidelines on how to use these drugs. At present, this is still common.