A study analyzing physician participation in the Medicare program from 2009 to 2016 found the number of physicians from the largest practices increased from 32.1% to 48.8%, while the number from hospital-owned practices increased from 18.1% to 25.8%, researchers reported in the Annals of Internal Medicine. Physicians who entered the Medicare program were more likely than those exiting to be part of a large practice compared with a small group practice, or with a hospital-owned practice compared with an independent practice.