Diabetes screening tests made easier

Canadian doctors have another option when testing people for Type 2 diabetes.

Single measurement considers average blood glucoses levels over about 3 months

Canadian doctors have another option when screening people for Type 2 diabetes.

On Monday, the Canadian Diabetes Association unveiled its 2013 Clinical Practice Guidelines to prevent and manage diabetes. It's estimated a third of Canadians will have either diabetes or prediabetes by 2020.

People age 40 and older should check for diabetes, says Dr. Alice Cheng of the Canadian Diabetes Association. (CBC)

The group hopes that a new standardized blood test, called the A1C, will encourage everyone over the age of 50 to get screened once every three years. The single measurement considers average blood glucoses levels over about three months.

The A1C does not require people to stop eating for 12 hours before taking the test as was the case previously. The test can also diagnose prediabetes before full-blown diabetes occurs.

"Pre-diabetes I like to think of as the waiting room to diabetes," said guideline chair and Toronto endocrinologist Dr. Alice Cheng. "We want to be able to identify who is sitting in that waiting and get them out of there as much as we can."

Through lifestyle interventions such as diet changes, exercise, losing weight, quitting smoking and self management of blood glucose levels, the group aims to prevent people with prediabetes from worsening. In some cases, blood sugar- and cholesterol-lowering drugs will also be prescribed. 

Diabetes and Cardiovascular Disease ABCDEs

Heart disease is a major cause of death and disability for people living with diabetes. The new guidelines encourage them to know their heart health ABCDEs and work to educate healthcare teams to address them:

  • A – A1C (a measure of average blood glucose) in optimal range.
  • B – Blood pressure optimally controlled.
  • C – Cholesterol in target range.
  • D – Drugs - heart-protecting medications for the right patients.
  • E – Exercise and other lifestyle measures.
  • S – Stop smoking.

Overall, the group's message for health care professionals was to screen wisely and diagnose precisely since doctors can't treat what they don't know.

However, British epidemiologists have questioned whether screening more people saves more lives.

When Dr. Simon Griffin of the Addenbrooke Hospital in Cambridge compared mortality over 10 years in the United Kingdom, he found screening for Type 2 was not associated with a reduction in deaths from all causes, cardiovascular or diabetes.

"The benefits of screening might be smaller than expected and restricted to individuals with detectable disease," Griffin concluded in the October edition of the medical journal The Lancet.

Screening those with risk factors makes more sense than testing everyone over the age of 40, he said in an interview, adding that since diabetes tests have few risks there is little harm beyond questions of the best use of public health dollars.

"The problem of course with this prediabetes label is it actually labels people and has them living with a lifelong concern about their diabetes when in fact they might have perfectly normal blood sugar levels, they may be otherwise perfectly healthy people," agreed drug policy research Alan Cassels of the University of Victoria.

The ultimate goal of the guidelines is to avoid serious complications from diabetes such as kidney disease, heart attacks and strokes.

The guidelines were published in the Canadian Journal of Diabetes and on the Canadian Diabetes Association's website with interactive tools and resources for health care providers and people living with diabetes.

With files from CBC's Kelly Crowe