The use of US health insurance data for surveillance of rare disorders: hereditary hemorrhagic telangiectasia

Purpose: To assess the utility of US health insurance data for surveillance of hereditary hemorrhagic telangiectasia, an autosomal-dominant blood vasculature disorder with an estimated prevalence of 1.5–2.0 per 10,000 persons worldwide. Methods: We used 2005–2010 MarketScan Research Databases to identify individuals with employer-sponsored health insurance and International Classification of Disease, 9th Revision, Clinical Modification codes of 448.0 present in either one inpatient claim or two outpatient claims 30 days apart to define hereditary hemorrhagic telangiectasia. We examined frequencies of International Classification of Disease, 9th Revision, Clinical Modification codes for conditions that are complications of hereditary hemorrhagic telangiectasia among individuals with hereditary hemorrhagic telangiectasia and the general population to identify combinations of codes associated with hereditary hemorrhagic telangiectasia. Results: Excluding observations from one state, the average prevalence of hereditary hemorrhagic telangiectasia was 0.3 per 10,000 persons. The reported prevalence rose with age from ~0.1 per 10,000 at ages