You may soon get a call from your doctor if you've let your gym membership lapse, made a habit of picking up candy bars at the check-out counter or begin shopping at plus-sized stores. That's because some hospitals are starting to use detailed consumer data to create profiles on current and potential patients to identify those most likely to get sick, so the hospitals can intervene before they do. Information compiled by data brokers from public records and credit card transactions can reveal where a person shops, the food they buy, and whether they smoke. The largest hospital chain in the Carolinas is plugging data for 2 million people into algorithms designed to identify high-risk patients, while Pennsylvania's biggest system uses household and demographic data.