24 August 2011
Is Pioglitazone Safe?
At last, we have clear guidance from the European Medicines Agency on the use of pioglitazone in people with diabetes in light of the new evidence of an association with bladder cancer. They conclude that there may still be benefits from pioglitazone in people with Type 2 diabetes but without either bladder cancer or uninvestigated hæmaturia.
This seems very simple but the if’s and but’s again invade the topic.
The numbers are very small. In a population of 10,000 people, 7 will develop bladder cancer. In the same population with Type 2 diabetes treated with pioglitazone, 16 will develop bladder cancer. However, people with Type 2 diabetes regularly have their urine checked for hæmaturia in a way that people without diabetes do not. Who is to say that some people without diabetes have undetected bladder cancer?
As ever, it boils down to a benefit versus harm question so let’s look at the figures.
If you treat 10,000 people with Type 2 diabetes with pioglitazone, 9 will develop bladder cancer who would not otherwise have done so. On the other hand, with regard to cardiovascular disease, pioglitazone will prevent cardiovascular disease in a number of cases. How many? That has yet to be established.
Can we say anything at all about the benefits of pioglitazone? Yes, because a recent study showed that in a population of 10,000 people with impaired glucose tolerance, 1,670 will develop diabetes whereas, in the same population treated with pioglitazone, only 500 will develop diabetes.
These are large numbers compared with the 9 that could develop bladder cancer.
What is extremely silly is to follow the advice of some consultants and change people taking pioglitazone which probably will help to prevent cardiovascular disease onto a sulphonylurea which almost certainly increases the risk of cardiovascular disease by about 30%.
That is not evidence-based medicine.
So ,what is the bottom line? Continue to use pioglitazone (because there is no sensible alternative) but monitor regularly for hæmaturia.