A Cochrane review in 2013, a BMJ paper in 2014, and most recently a literature review from the Mayo Clinic in Rochester, Minn., have all investigated the evidence and found it lacking.
The theory is that using medication to tightly control blood sugar in type 2 diabetes will prevent the deterioration of tiny blood vessels, which can lead to damage in kidneys, eyes and other parts of the body, a composite outcome called "microvascular complications."
Curiously, the studies failed to show a corresponding drop in the risk of blindness, nor a reduction in the rate of kidney failure.
In medical journalism, it's a major challenge trying to reflect the uncertainty that is inherent in biomedical research. There's a perception that science delivers straightforward, objective answers. But interpretations can be surprisingly subjective, even though everyone is using the same data.
Witness the raging debate over the use of statins that has pitted two of the world's most prestigious medical journals in an increasingly heated argument over the evidence for some of the most commonly prescribed drugs in the world.
No one is suggesting that the drugs be tossed out, or that attention to glucose control should be recklessly abandoned.
But today, most patients have no symptoms. They find out they have Type 2 diabetes after a routine blood test. Should they also be given drugs to hit the tight glucose levels? This is where the evidence gap lies.
Back in her home on Vancouver Island, Cait O'Sullivan continues her work for the B.C. Ministry of Health, educating family doctors about the evidence behind the drugs they're prescribing. When she tells them about the debate over type 2 diabetes drugs, they are often surprised.
It's a debate that can only be resolved with more study and better data. That's why O'Sullivan's group is calling on Health Canada to demand better evidence when they approve type 2 diabetes drugs.
Right now Health Canada only requires evidence that the drugs lower blood sugar, and don't increase the risk of cardiovascular disease.
Please read both links as I only picked some of the material.