This is a new, large observational study, which muddies up the field of SGLT2 inhibitors. It links use of SGLT2 inhibitors in general with a 2x risk of lower limb amputation and of Diabetic Keto Acidosis.
So far, one SGLT2 invibitor (invokana/Invokamet, or canagliflozin) had been linked with higher amputation risk, but the others (dapagliflozin and empagliflozin) were not.
In this study, only 1% of SGLT2 patients were taking canagliflozin: the other 99% were taking dapagliflozin or empagliflozin.
Here is a discussion of the study on WebMD:
It is important to note that this is an observational study only: it finds links between use of SGLT2 inhibitors and amputation/DKA, but it cannot prove a causal relationship between the two.
The study attempted to account for a number of factors before reporting the link.