John Hopkins University have conducted some interesting research into the social habits of physicians. I think the key takeaway from the study is that healthcare professionals are using social media, but they're primarily using peer communities that allow them to filter out the nonsense and talk with people they know will add value to their lives.
“What did surprise us was the heavy use of online physician-only communities,” said Robert Millar, a researcher on the project. “It’s possible that many physicians feel more comfortable with that type of social media instead of a more public space like Twitter or Facebook.”
This finding chimes with research last year showing that most professionals engage socially on peer communities rather than the wider social media.
Read more about the John Hopkins study here