The economic burden of Medicare-eligible patients by multiple sclerosis type.

Objective: Although the global rate of multiple sclerosis (MS) is low, a few studies have documented high costs. Costs are highly variable depending on MS stage. This study was designed to assess the economic burden of Medicare-eligible patients by MS type in the United States using a claims-based classification algorithm to examine cost variation by disease stage.

Methods: A sample of 2003 to 2006 Medicare patients was selected. Cases were classified as pre-existing progressive MS or pre-existing relapsing-remitting MS (RRMS); the latter were further subdivided into relapsing, remitting, or stable.

Results: The sample had 5044 MS subjects, of whom 34.4% had prevalent progressive MS and 65.6% had prevalent RRMS. There were many chronic, comorbid conditions. The mean all-cause Medicare expenditures (not including self-administered medications) per person-year for MS in 2006 were $23,630 for prevalent progressive patients and $5887 for prevalent RRMS patients. Within the RRMS type, Medicare expenditures per person per month in 2006 were $1418 for relapsing patients, $608 for remitting patients, and $331 for stable patients.

Conclusions: There are substantial cost advantages to Medicare for keeping RRMS patients in a stable health state and in keeping them from advancing in disability severity. The overall cost advantage would be diminished by the large cost burden of comorbidity, which would likely remain fixed with improved MS therapies.