Burden of Parkinson's Disease by Severity: Health Care Costs in the U.S. Medicare Population.

Background: Current understanding of the health care costs of Parkinson's disease (PD) and the incremental burden of advanced disease is incomplete.

Objectives: The aim of this study was to assess the direct economic burden associated with advanced versus mild/moderate PD in a prevalent national sample of elderly U.S. Medicare beneficiaries with a PD diagnosis.

Methods: Analyzing 100% fee-for-service Medicare claims from 2013, we defined advanced PD with a medication-based algorithm and calculated all-cause and PD-related costs for the overall sample and by disease severity. We measured primary PD-related costs (based on claims with a primary diagnosis of PD) and any PD-related costs (based on claims with PD in any diagnostic field). Generalized linear models were used to estimate risk-adjusted mean cost differences between the advanced and mild/moderate PD groups for the calendar year.

Results: The final sample (N = 144,703) had mean observed all-cause, primary PD-related, and any PD-related costs of $23,041 (SD, $34,045), $3429 (SD, $7431), and $9924 (SD, $22,140), respectively. Twenty percent of patients were classified as advanced PD. Costs varied substantially; any PD-related mean costs were $483 for the lowest patient decile (which included 1% of the advanced group) and $48,145 for the highest decile (which included 15% of the advanced group). Incremental risk-adjusted costs of advanced PD were $5818 (95% confidence interval [CI]: $5411-$6225) for all-cause costs, $3644 (95% CI: $3484-$3806) for primary PD-related costs, and $6088 (95% CI: $5779-$6398) for any PD-related costs.

Conclusions: Elderly Medicare beneficiaries with PD had substantial variation in PD-related costs. Advanced PD was associated with a larger economic burden than mild/moderate PD. © 2020 International Parkinson and Movement Disorder Society.