ACOs suffer astonishingly high turnover rates among their doctors and patients; their patients are unusually healthy; and those unusually healthy ACO patients constitute about 5 percent of each ACO doctor’s panel of patients. These facts appear in three recent reports: CMS’s final evaluation of the Pioneer ACO program, and two papers published in Health Affairs by John Hsu et al.
Each of these facts – high turnover, healthier patients, and few ACO patients in each physician’s panel – poses problems that cannot be solved without a substantial redefinition of the ACO. How are doctors supposed to influence the health and cost of patients they see only sporadically or not at all? How are ACO doctors supposed to lower costs if their sickest and most costly patients are not in the ACO? How are ACOs supposed to alter physician behavior when their physicians see fewer than 100 ACO patients out of a typical panel of 1,500 to 2,000 patients?