It is a play on words, or a joke.
There is a saying in English, that patience is a virtue. "patience" in this case means the ability to wait for something important and to not rush things. But the word is pronounced exactly the same as another English word "patients". A patient is someone who is being treated by a doctor. For example, you can say "the doctor treats ten patients each day".
So, in the economist article, they are playing a joke with the expression "patience is a virtue" by saying that in the medical profession having more patients is not always a good thing, or a virtue.