blood tests

Type 2 diabetics with good blood sugar control don’t need multiple tests

by Barbara Hewitt on December 11, 2015

Many people with type 2 diabetes, especially those whose blood sugar levels are under control, may be subjected to too many tests, a new study in the United States suggests.

They are getting unnecessary blood sugar tests and, in some cases, needless changes in medication. Researchers also pointed out that guidelines actually suggests that haemoglobin A1C tests, which measure a person’s average blood sugar control, should be done only once or twice a year if blood sugar control is good.

Blood-TestAll of the patients in the study of 31,000 people with type 2 diabetes had good blood sugar control yet nearly 55% underwent A1C tests three or four times per year. Another 6% had at least five tests per year.

“I think part of the problem is that we often think more testing is better,” said lead researcher Dr. Rozalina McCoy, a professor of medicine at the Mayo Clinic, in Rochester, Minnesota.

But, as in other areas of medicine, that is not necessarily true in diabetes care, McCoy explained.

She also pointed out that there are potential risks to patients’ health, for example, in this study, frequent A1C tests raised the odds that patients would be started on additional medications to control their blood sugar.

The worry, McCoy said, is that those more intense regimes would boost patients’ risk of dangerously low blood sugar.

All of the adults in the study had A1C levels that were consistently below 7% within the previous two years, which meant their blood sugar was under good control. In general, McCoy said, there’s little chance that such patients would benefit from having A1C tests more than once or twice a year. Yet, most patients were tested more often than that over the study period.

Indeed, at a certain point, tighter control has diminishing returns, according to Dr. Rodney Hayward, a professor of medicine at the University of Michigan, in Ann Arbor. He said that clinical trials have found that lowering A1C from 8.5% to 7% can modestly lower heart attack risk but there’s also evidence that tight blood sugar control can shorten people’s lives.

He also explained that blood sugar is not the only thing that matters. Getting high blood pressure under control and taking a statin are actually the most effective ways to cut the risk of diabetes complications like heart disease and kidney failure.

The study couldn’t uncover the reasons for overzealous A1C testing. It’s possible, McCoy said, that many doctors, or patients, prefer close monitoring.

“One of the hardest things for doctors is to do less,” said McCoy.

Fragmented care could be another reason. McCoy explained that those in the study with multiple doctors were more likely to receive three or more tests a year.

The research also found that after 2009, excessive A1C testing started to decline. “That’s encouraging. We don’t know what’s driving the change. But it may be related to growing awareness that tight blood sugar control may not benefit patients,” said McCoy.

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