The following originally appeared on The Upshot (copyright 2019, The New York Times Company).
More than 30 million people in the United States have diabetes. The vast majority of them have Type 2 diabetes. Some of those are testing their blood sugar at home, but the best research is telling us that they don’t need to — that in fact it’s a waste of money.
It’s not a small problem. The waste is running into the billions of dollars, and it’s costing all of us money through the health care system.
For people with Type 1 diabetes, blood glucose monitoring and insulin administration is the standard of care. Patients need to check their blood sugar a number of times a day, then give themselves insulin to replace what would have been made in the pancreas. Treatment for Type 2 diabetes, however, doesn’t involve these critical calculations of insulin. It’s usually maintained with pretty regular administration of the same drugs on a set schedule.
Self-monitoring for blood glucose, therefore, may be unnecessary for those not on insulin. This has been tested in well-designed studies.
The Monitor trial, published two years ago in JAMA, was a pragmatic trial that took place in 15 primary care practices in North Carolina. Patients with Type 2 non-insulin-treated diabetes were randomly assigned to one of three groups.
People in the first group were told to check their blood glucose once a day. People in the second were told to check their blood glucose once a day, and then were given tailored advice depending on the results from the meter. The third group was told not to check blood sugar at all.
After one year (a pretty impressive length for a study like this), there were no differences in the hemoglobin A1C levels (the best way to monitor long-term blood glucose control) between the three groups. There were also no differences in the health-related quality of life measures for the patients. There were no differences in the number of times they experienced hypoglycemia, how much care they needed, and how many progressed to the need for insulin.
In other words, there were no measurable differences in how patients fared, whether they checked blood sugar or not.
This evidence, while the best to date, confirmed what previous work had shown. A 2012 Cochrane review assessed all the randomized controlled trials through 2011 that had investigated how testing for blood glucose at home improved outcomes. It included 12 trials involving more than 3,200 patients. By 12 months, the overall benefit to testing, with respect to lab values, was statistically insignificant. There were never any benefits with respect to patient satisfaction.
Still, not everyone is on board. Critics of this most recent trial said it didn’t prove that blood glucose monitoring couldn’t help: It’s possible that with better training, or more attention to detail, there might be ways to make this work.
The point of pragmatic comparative effectiveness trials like this, though, is to test how practices work in the real world. In these high-quality primary care practices, even with customized help in interpreting the measurements (which is more than most patients get), testing blood sugar didn’t make a difference.
Choosing Wisely an educational campaign aiming to reduce unnecessary medical tests and procedures, advises against routine home glucose monitoring for patients with Type 2 diabetes who are not on insulin. It says that there is no benefit, and that there are potential harms (like an association with increased anxiety). This argument is supported by the American Academy of Family Physicians, the Society of General Internal Medicine and the Endocrine Society.
Of course, there are exceptions. When patients are acutely ill, or changing regimens, or finding that their blood sugar is not well controlled, testing may be appropriate. Such decisions should be made in consultation with a physician.
But for most people with Type 2 diabetes not on insulin, testing is inappropriate most of the time. That message is not getting through. At the end of last year, another study was published in JAMA Internal Medicine that quantified the prevalence of glucose testing in adults. Researchers examined a database that contained data on more than 370,000 commercial health insurance and Medicare Advantage beneficiaries who had Type 2 diabetes.
Of the more than 23 percent of patients who were using testing strips, more than half were probably doing so in spite of widespread recommendations that they shouldn’t. They were using a median of two testing strips a day at a cost of more than $325 per year per patient.
With a health care system as complicated as ours, it’s hard to take money from one pot and shift it easily to another. Efficiency in each system is crucial. The fact that a necessary facet of diabetes care is increasingly out of reach — while unnecessary and potentially harmful care is easily overused — illustrates how much work still needs to be done.