Cost-of-illness of scleroderma: the case for rare diseases.

OBJECTIVE: To determine the societal costs of scleroderma (SSc), a rare chronic connective tissue disease that affects approximately 98,000 Americans. Lack of reliable national databases limit rare disease cost studies, and this study suggests methods of using multiple data sources to assess the costs of rare diseases.
METHODS: Primary and secondary data sources were used to calculate direct and indirect costs of SSc, including discounted lifetime mortality and morbidity costs. A prevalence-based, human capital approach was used. Sensitivity analyses were used to vary parameters that are uncertain, such as prevalence, mortality, and labor costs.
RESULTS: Annual direct and indirect costs of SSc in the United States are $1.5 billion. Morbidity represents the major cost burden, with costs of $819 million (56%) of total costs. The current value of lifetime earnings lost was $179 million (12%) or $300,000 per death. Direct costs were $462 million (32%) or $4,731 per person annually, indicating that costs are spread over the long disease duration.
CONCLUSIONS: This study provides one model for the assessment of rare disease costs. Triangulation of data sources and sensitivity analyses are important for determining the costs of rare diseases. The high cost of SSc, despite its low prevalence, suggests that the burden of rare chronic diseases can be high. The high morbidity costs reflect the young age of onset of the disease as well as the need for treatments to decrease morbidity costs. Local shared databases and national surveys are needed to improve cost estimates of rare diseases.