Increased Risk of Lower Limb AmputationsAs reported on Medscape The European Medicines Agency (EMA) which is the European equivalent of the FDA announced on February 10, 2017 that a warning stating that the sodium glucose cotransporter 2 (SGLT2) inhibitors for type 2 diabetes may increase the risk for lower-limb amputation should be included in the prescribing information for all drugs in this class.
In Medscape's words, "The warning from EMA's Pharmacovigilance Risk Assessment Committee (PRAC) issued today cites data from two ongoing clinical trials with canagliflozin (Invokana, Vokanamet, Janssen) in patients at high risk for cardiovascular events, Canagliflozin Cardiovascular Assessment Study (CANVAS) and a related study of renal end points, CANVAS-R."
Quoting the EMA the article points out that "In a 4.5-year interim analysis of CANVAS, the independent monitoring committee for the trial found that the rate of amputations per every 1000 patients was equivalent to seven for 100 mg/day and five for 300 mg/day of canagliflozin compared with three per 1000 patients taking placebo. Most of the amputations were of toes." Note that this means that there were from one and two thirds more to more than twice as many amputations in the group taking the drug as occurred in the placebo group.
As you can see if you read the comments to the Medscape new release, some people claiming to be doctors and a pharmacist immediately argued that this was because the patients given the SGLT-2 inhibitors were sicker and more likely to have amputations. People posting comments on Medscape are not required to reveal if they are on the payroll of the companies who are earning several billion dollars a year selling these heavily advertised new drugs. Nor are they required to validate their identity, so any employee of a drug company could post these comments using a made up doctor's name.
Lest you be swayed by their arguments against believing the EMA's experts, note that this data was from a controlled study. This means that both the group taking the drug and the group taking a placebo were matched for characteristics which would have included their blood sugars, age, and time since diagnosis. Since the groups had the same characteristics, the higher rate of amputations is very likely to be a result of something the drug does to the blood supply of the toes. The EMA doesn't lightly decide to add a serious warning to the label of a drug.