Taking medication to tightly control and lower blood glucose levels is the advice frequently given by doctors to the 400,000 B.C. residents with Type 2 diabetes — but it’s a “misguided” approach, according to the University of B.C. Therapeutics Initiative.
More than $1 billion is spent annually on diabetes drugs in this province, but in its latest bulletin to doctors, the TI says a growing body of research casts doubt on the effectiveness of Type 2 diabetes treatment. Doctors should focus instead on prescribing lifestyle modifications such as weight loss, exercise and healthier diets instead of medications to many patients, it says.
Type 2 diabetes, characterized by resistance to insulin, is largely caused by obesity, lack of exercise, high-carbohydrate diets and aging.
With the exception of a drug called metformin, many glucose-lowering medications like insulin can lead to weight gain or potentially cause low blood sugar (hypoglycemia), which can lead to falls, driving accidents or even loss of consciousness, the TI says. More than half of Type 2 diabetes patients take such medications. (Insulin is an essential medication for those with Type 1 diabetes, which accounts for less than 10 per cent of all diabetes cases in B.C.).
The TI, an independent body that provides advice to doctors, said the optimal blood glucose level target is actually unknown in Type 2 diabetics, and there’s still no conclusive evidence that taking medications to lower blood glucose levels will decrease complications of the condition. Such complications include kidney disease, blindness, cardiovascular disease, strokes and amputations.
Dr. Tom Perry, a Vancouver internist and clinical pharmacologist with the TI, said doctors tend to minimize harms when prescribing drugs to patients.
At the same time, he says that he’s had few “star” diabetic patients willing to put in the hard work to shrink waistlines, exercise and change diet patterns.
“It’s kind of frightening because we don’t really have the right evidence for treating the Type 2 epidemic. What we’ve been doing is not very scientific,” he said, adding that publicly funded (as opposed to pharmaceutical industry-sponsored) research trials are needed to study the best treatment approaches.
Vancouver endocrinologist Dr. Tom Elliott said he’s in general agreement with the TI that some doctors may be over-treating Type 2 diabetics.
“But there are lots of patients we may be under-treating too. The problem is we don’t know how low the glucose levels should go in order to reduce the risk of bad things happening to patients.”
In an article he wrote last fall, Elliott discussed the growing controversy, saying it is true that in borderline patients, there is little high quality evidence regarding glucose lowering drugs for preventing long-term complications.
“What’s clear is that a concerted effort needs to be made to help high-risk groups to achieve better blood sugar control,” Elliott wrote.
Lawrence Leiter, a professor of medicine and nutritional sciences at the University of Toronto and a specialist in the division of endocrinology at the city’s St. Michael’s Hospital, was critical of the TI bulletin. He said the TI group has been overly selective in choosing which studies to base its recommendations upon.
“In the past two years, we have evidence from large, well-conducted, randomized controlled trials that three different medications for the management of diabetes — empagliflozin (Jardiance), liraglutide (Victoza) and semaglutide (not yet approved) — significantly reduced the risk of cardiovascular events in patients with a history of diabetes and cardiovascular disease, and that empagliflozin also reduced the risk of kidney problems.
“Canadian Diabetes Association clinical practice guidelines have for many years emphasized that we must not just lower blood glucose levels but also improve all risk factors, including blood pressure and cholesterol (and) the most recent update to our guidelines, published in November 2016, now recommend the use of empagliflozin and liraglutide to reduce the risk of complications in appropriate patients.”
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