Cost of caring for Medicare beneficiaries with Parkinson's disease: impact of the CMS-HCC risk-adjustment model.

Previous studies have demonstrated that Medicare risk-adjusted capitation models do not adequately compensate programs serving primarily disabled or frail populations. Using the Medicare Current Beneficiary Survey, we demonstrate that the Centers for Medicare and Medicaid Services-Hierarchical Condition Categories (CMS-HCC) model calculates Medicare capitation payments for Parkinson's patients more accurately than for the general population. The discrepancies between the predicted and actual expenditures estimated at various disability levels were smaller for Parkinson's patients than for other beneficiaries. If the CMS-HCC payment model were to apply to programs that draw a significant percentage of their participants from the Parkinson's disease community, these programs likely would be compensated fairly.