Carolinas HealthCare System is taking a big Big Data approach to patient profiling. Bloomberg Businessweek reports that the regional system, which operates medical centers in the Carolinas, is tracing patient behaviors—such as food purchases, lack of gym attendance—to identify high-risk patients in the hope that this information can help doctors modify patient behaviors and keep potential problems from becoming major health issues.

As Bloomberg’s thought-bubble illustration puts it, this insight will allow physicians to add exposition-style dialogue such as “I know about the 2 am Papa John’s deliveries” while a patient walks a healthcare provider through her lifestyle habits.

Carolinas HealthCare tells Bloomberg it is getting the patient information from data brokers, who keep tabs on things like store loyalty program and credit card purchases.

Bloomberg notes that Carolinas HealthCare System says that it will not really be able to grab specific transaction information, but that the system will be able to use consumer behavior to create predictive analytics which can act as an overlay for patient information and risk. An example: sporadic prescription refills charged on credit cards could be resolved with an intervention, such as having nurses call patients about refills, while asthmatic cigarette buyers could be flagged as potential emergency room visitors for asthma attacks.

Privacy advocates tell Bloomberg they are concerned this sort of patient knowledge could erode the doctor-patient relationship, and turn a conversation into “a potential inquisition about behavior.”

Patients also have limits. Type 1 diabetes patient Jorjann Murry told Bloomberg she usually ignores her health insurer’s calls about her health habits because she finds them intrusive.