Prevalence and disease burden of primary restless legs syndrome: results of a general population survey in the United States.

To assess prevalence, disease burden, and costs of primary Restless Legs Syndrome (RLS) in the US. In 2007, 61,792 (20%) of 313,000 subjects from a representative US panel completed an online "global opinions" survey identifying respondents reporting all four diagnostic features of RLS. 4,484 met all criteria. 1,400 were randomly selected to complete a questionnaire to exclude those with diagnoses indicating possible secondary RLS. Those that did not have diagnoses associated with secondary RLS were asked to complete the Cambridge-Hopkins RLS questionnaire to exclude RLS mimics. Prevalence was estimated for the following groups: (1) RLS symptomatic, (2) primary RLS, and (3) primary RLS sufferers (symptoms ≥2/wk with moderate-to-severe distress). The primary RLS completed a larger online survey including the IRLS, EuroQol, Work Productivity and Activity Impairment questionnaire, and questions about healthcare resource use. The validated diagnostic tools and exclusion of medical conditions likely to cause RLS provide a very conservative estimate of US census-weighted prevalence of 2.4% for primary RLS and 1.5% for primary RLS sufferers. About 33% of respondents had a physician diagnosis of RLS. Primary RLS sufferers had a mean productivity loss of 1 day/wk. All RLS-related costs increased with RLS symptom severity, with increasingly significant decrements in health status, sleep disturbance, and work productivity. Even this very conservative approach finds RLS in this cohort to be common, under-diagnosed, and carried a significant personal and social burden.