Direct medical costs associated with Parkinson's disease: a population-based study.

The objective was to provide population-based estimates of incremental medical costs associated with Parkinson's disease (PD) from onset forward. All Olmsted County, Minnesota, residents with confirmed PD onset from 1987 through 1995 (n = 92) and one age- and sex-matched non-PD referent subject per case were identified with retrospective record review and followed in provider-linked billing data for direct medical costs (excluding outpatient pharmaceutical costs) from 1 year before index (i.e., year of symptom onset) through 10 years after index. Costs for each referent subject were subtracted from those for his/her matched case. Tests for statistical significance used Wilcoxon signed ranks. Preindex costs were similar [median difference in annual costs (MD) = -3 dollars; P = 0.59]. One year post index, PD subjects exhibited borderline significantly higher costs compared to referent subjects (MD = 581 dollars; P = 0.052); the difference diminished over 5 years (MD = 118 dollars; P = 0.82). By 5 to 10 years, however, PD subjects exhibited significantly higher costs (MD = 1,146 dollars; P = 0.01). Over the full 10 years, excess costs were concentrated among PD subjects without rest tremor (MD = 2,261 dollars, P < 0.01, for those without tremor and -229 dollars, P = 0.99, for those with tremor). These population-based estimates of PD-associated direct medical costs from onset forward can uniquely inform policy decisions and cost-effectiveness research.