Using "Ob" in this way means the question is a suggestive question.
The person stating the question clearly implies the answer is expected to be "No."
In this example the reader is supposed to read "No, the patients probably do not know about the way they are treated." between the lines.
If I tried to translate it to English (not literally, and maybe a bit exaggerated) it might be
But are patients really aware that they are being treated with home
remedies?
The version of the question without the "ob", starting with "ist", is a much more neutral form to state the question.
@harald-lichtenstein is right that the "ob" sentence is an ellipsis: the missing words are exactly the words evoking the suggestive part, i.e. creating doubt that the patients know.