When it comes to type 2 diabetes, aggressive treatment is not necessarily better. Many people are taking unnecessary diabetes — and other — medications when their diabetes is already well-controlled. Over-treating diabetes in this way greatly increases their risk of severe low blood sugar, hypoglycemia, a study has found. In fact, for older patients and for patients who have other medical conditions in addition to type 2 diabetes, the risk of dangerously low blood sugar is nearly doubled.

A key indicator of diabetes severity is a person's hemoglobin A1C (HbA1C) level. While treatment guidelines differ, most call for starting or intensifying treatment in adults when HbA1C is above 6.5 or 7.0. Yet this study found many people starting treatment or being prescribed additional diabetes drugs when their HbA1C level was much lower.

While intensive treatment raised the risk of hypoglycemia severe enough to require medical attention for everyone in the study, it raised it much more for older and sicker patients, nearly doubling it.

Reducing HbA1C levels below these recognized levels is not likely to improve patients' health, according to the researchers (and most guidelines); and this study suggests that it may harm it — intensive treatment is overtreatment.

The study looked at over 30,000 adults with type 2 diabetes who had two consecutive tests showing HbA1C less than 7.0. None were treated with insulin or had episodes of severe hypoglycemia in the preceding 12 months, both known risk factors for future incidents of hypoglycemia.

It found that younger and healthier patients were better able to tolerate intensive treatment, at least as far as hypoglycemia was concerned. While intensive treatment raised the risk of hypoglycemia severe enough to require medical attention for everyone in the study, it raised it much more for older and sicker patients, nearly doubling it.

Over one-quarter of the patients in the study were receiving intensive treatment.

People in the study who were 75 or older or who had end-stage kidney disease or dementia or three or more serious chronic conditions (in addition to diabetes) had a higher risk of serious hypoglycemia during the two-year study than younger or healthier patients, 1.77% to 1.02%.

This risk rose when people were receiving intensive diabetes treatment, especially for the older/sicker group. Their risk rose to 3%. Younger/healthier diabetics saw a smaller increase, to 1.3%.

“This means that 3 out of 100 older or clinically complex patients with diabetes who never had hypoglycemia before, whose HbA1C is within recommended targets, and who are not on insulin, will experience a severe hypoglycemic episode at some point over two years,” explained Rozalina McCoy, the study's lead author and an endocrinologist and primary care physician at the Mayo Clinic in Rochester, Minnesota.

“This does not even capture the more mild episodes of low blood sugar that patients can treat at home, without having to go to the doctor, emergency department or hospital,” she added.

For purposes of the study, intensive treatment meant:

  • Having an HbA1C of 5.6 or below on the second test and taking any diabetes medication on that date or being prescribed a new medication afterwards.

  • Having an HbA1C from 5.7-6.4 on the second test and taking two or more medications at the time of the test or being prescribed any additional medication after the test.

  • Having an HbA1C of 6.5-6.9 on the second test and being prescribed two or more new drugs (or insulin) after the test.

    • Controlling blood sugar is important for people with type 2 diabetes, but even though young and relatively healthy patients may tolerate intensive treatment reasonably well, the benefits of aggressive treatment are uncertain, the authors warn; and it nearly doubles the risk of severe hypoglycemia among those who are elderly.

    The study appears in JAMA Internal Medicine.