Johnston KJ, et al. - In this retrospective observational study, researchers determined whether factors not included in Medicare risk adjustment, including patient neuropsychological and functional status, as well as local area health resources and economic conditions, are correlated with Medicare total annual cost of care (TACC), and assessed whether accounting for these factors is related to improved TACC performance by outpatient safety-net clinicians. Study participants included 111,414 unique identifiable physicians, and the final weighted sample included 213,904,324 patient-years from 30,058 unique patients (58.1% women). According to findings, neuropsychological and functional impairment is common among Medicare beneficiaries and is related to increased annual Medicare expenditure. If these factors are not taken into account, outpatient clinicians who care for these vulnerable groups, such as safety net clinicians, may be inappropriately penalized for factors that are likely beyond their control.