Scientists find too much testing could be harmful for some type 2 diabetics

by Barbara Hewitt on June 8, 2016

Over testing and too much of a focus on glycated haemoglobin (HbA1c) levels can lead to serious harm for people with type 2 diabetes whose condition is well controlled, according to a new scientific study from the United States.

Researchers from the Mayo Clinic were surprised to find high levels of over testing, perhaps prompted by advertising and media campaigns, and this could be leading to more medication being used to keep HbA1C levels within desired targets.

The team believes this can be an issue for older patients with other medical conditions as the study found that intensive treatment nearly doubled the risk of severe hypoglycaemia requiring medical attention, including hospitalisation.


“At first, we were surprised to find how much over testing for HbA1C is occurring among adults of all ages with type 2 diabetes who were already well controlled,” said Rozalina McCoy, a Mayo Clinic primary care physician and endocrinologist and lead author of the study.

“But, then, we realised that not only were patients being tested frequently, they were also being treated with more medications than we would expect considering how low their HbA1C already was. So, this led us to do this study to see how frequently patients are treated so intensively that they may be over treated and what that does to their risk of hypoglycaemia,” she added.

She pointed out that hypoglycaemia is a serious potential complication of diabetes treatment. It worsens quality of life and has been associated with cardiovascular events, dementia and death.

“Treating patients to very low HbA1c levels is not likely to improve their health, especially not in the short term, but can cause serious harms, such as hypoglycaemia,” she added.

For the purposes of the study intensive treatment was defined as being treated with more glucose lowering medications than clinical guidelines consider necessary given a patient’s HbA1C level. Patients whose HbA1C was less than 5.6%, diabetes is defined by HbA1C of 6.5%, were considered intensively treated if they were taking any medications.

Patients with HbA1C in the prediabetes range of 5.7% to 6.4% were considered to be intensively treated if using two or more medications at the time of the test, or if started on additional medications after the test, because current guidelines consider patients with HbA1C less than 6.5% to be optimally controlled already. For patients with HbA1C of 6.5% to 6.9%, the sole criteria for intensive treatment was treatment intensification with two or more drugs or insulin.

The researchers examined medical claims, pharmacy and laboratory data of 31,542 adults with stable and controlled type 2 diabetes. None of them were treated with insulin or had prior episodes of severe hypoglycaemia.

“Our goal was to specifically assess the degree to which intensive treatment, not other known risk factors such as prior hypoglycaemic events or insulin therapy, caused hypoglycaemia. We also wondered if young and healthy patients may be better able to tolerate intensive treatment than older patients or those with complex medical problems, so we specifically looked at the impact of intensive treatment on these two groups separately,” said McCoy.

The team found that 18.7% of clinically complex patients and 26.5% of non-complex patients were treated intensively. Clinically complex patients had nearly double the rate of severe hypoglycaemia than non-complex patients, and intensive treatment increased it by an additional 77%.

“These findings are concerning for many reasons. Over treatment results in greater patient burden, higher risk of medication side effects, and more severe hypoglycaemia, which can lead to serious injury and even death. It adds more unnecessary costs for patients and the health care system. And, at the same time, there is often little or no benefit from such intensive treatment, not in the long term and certainly not in the short term,” McCoy pointed out.

“As clinicians, we need to understand not only what tests and medications are necessary, but also determine which ones are not, and which ones may cause more harm than good. We need to individualise treatments to the needs and goals of our patients. My hope is that others will be able to apply our findings in their practices for the benefit of patients everywhere,” she added.


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