How will changes to Medicare Part D risk score model affect health plans?

In April, the Centers for Medicare and Medicaid Services (CMS) released details for the 2020 Medicare Part D pharmacy hierarchical condition categories (RxHCC) risk score model. The model change will affect health plans differently based on demographics and other factors. Overall the model change increased low-income risk scores and decreased non-low-income risk scores.

In this paper, Milliman’s Adrian Clark and David Koenig summarize the changes in member risk scores resulting from the risk score model update. They also quantify the model change using three separate metrics: the change to the model coefficients, the overall change in risk score for a nationwide population by key enrollee characteristics, and the change to the normalization factor.