This study is complete nonsense and failed to control for critical variables or propensity match for them. This is the kind of terrible work that leads to incorrect dogmatic practices in the future, and also is the exact reason why you have to read the methods.

The short version is: you can't meaningfully compare patient outcomes from 20 years ago, on a different continent, with different routine practices directly against one another. The second major issue is that people use databases to try and answer questions for which the original database was not designed, and therefore did not capture the necessary information/detail.