I don't think anyone would compare the two campaigns in terms of casualties. The article just suggests that the quality of the medical personnel was considerably better in 1823 and the organisation was better. This might just represent the fact that they were not so thinly spread.
That there was an ordonnance of 30 December 1814 suggests someone(Dupont?) considered whatever was being done about the teaching hospitals as a matter of urgency. The article doesn't say exactly what was done at that point. I will see if I can find anything.

Susan