Background: To our knowledge, no study to date has investigated the prescribing patterns of immunomodulatory agents (IMAs) in an outpatient setting in the United States. To address this issue, we performed retrospective data analyses on National Ambulatory Medical Care Survey (NAMCS) data for MS patient visits between 1998 and 2004.
Methods: NAMCS data are a weighted estimate of the nationwide frequency of patients' outpatient clinic visits.