In a study released online in December, researchers from Mayo Clinic report a national trend toward over-testing glycated hemoglobin (HbA1C) levels in adult patients with Type 2 diabetes.

Over-testing causes redundancy and waste says the study team, adding unnecessary costs and time burden for patients and providers.

In addition, excessive testing can result in over-treatment with hypoglycemic drugs, adding additional cost and potential health complications.

The best approaches to Type 2 diabetes monitoring and treatment are not well defined by professional societies and regulatory bodies. While lower thresholds of testing frequencies often are discussed, the upper boundaries are rarely mentioned.

Yet, most agree that for adult patients who are not using insulin, have stable glycemic control within the recommended targets and have no history of severe hypoglycemia or hyperglycemia, checking once or twice a year should be enough.

In practice, there is a much higher prevalence of excess testing.

“Our findings are concerning, especially as we focus more on improving the value of care we deliver to our patients ” says Dr. Rozalina McCoy, a Mayo Clinic primary care physician and endocrinologist who was the study’s lead investigator.

“As providers, we must be ever vigilant to provide the right testing and treatment to our patients at the right times — both for their well-being and to ensure the best value in the health care we provide.”

The investigators believe this study provides definitive evidence of such excess testing, after examining a national sample of 31,545 nonpregnant adults with controlled noninsulin-treated Type 2 diabetes.

Approximately 55 percent of patients in this cohort achieved and maintained the recommended level of less than 7 percent glycated hemoglobin and were tested three or four times a year. Six percent were tested five or more times.

McCoy notes that there are a number of potential reasons for high rates of testing. “Potential reasons for more frequent testing include clinical uncertainty; misunderstanding of the nature of the test (and) not realizing that HbA1C represents a three-month average of glycemic control; or a desire for diagnostic and management thoroughness,” she says.

Other times, it may be the result of fragmentation of care (because a patient has more than one unconnected provider); the need to fulfill regulatory demands, such as public reporting of performance metrics; or internal tracking systems.

“Because our culture often thinks that more is better,” she says, patients and providers may favor additional testing due to a desire for comprehensive care.

The researchers found that excessive testing increased the odds of over-treatment with one or more drugs, despite normal glycated hemoglobin levels. They also found that among patients receiving bundled testing (i.e., cholesterol, creatinine and HbA1C tests in the same day), rates of over-testing were lower.

“We hope that these findings will help inform decision-making for health care providers and patients everywhere,” she says.

The research was part of an ongoing commitment by the Mayo Clinic to improve health and enhance the way patients experience the delivery of health care. Through the Mayo Clinic Robert D. and Patricia E. Kern Center for the Science of Health Care Delivery and its collaborations across Mayo and around the world, Mayo’s vision is borne out.

The study used de-identified administrative, pharmacy and laboratory data from 2001 to 2011 reflecting the treatment of more than 150 million individuals of all ages and races from 50 states.

This large data source enabled researchers to investigate across a much broader patient base than previously available to health science researchers.