tor, emergency department (ED), or "other," as well as the number of CD-related hospital admission days. Unit costs were assigned to each type of health care resource using national non-Medicare 2011 reimbursement rates. Hospitalization cost was estimated using the HCUP.net mean daily cost of inpatient stay (principal diagnosis 333.83). Cost of an ED visit was estimated by the mean paid amount for ED visit (principal diagnosis 333.83) using commercial claims data. RESULTS: Baseline data were available for 786 participants at time of analysis. The mean age was 57.7 years, and the majority (76%) were female. The mean (SD) number of visits to a primary care provider was 1.4 (2.1), 1.9 (1.9) for neurologist, 0.7 (1.8) for physiatrist, 1.8 (3.8) for physical/occupational therapy, 0.2 (0.9) for neurosurgeon, 1.3 (3.1) for alternative care provider, 1.1 (3) for chiropractor, and 3.2 (2.7) for "other." Participants reported a mean(SD) of 0.2(0.9) visits to the ED and 0.1(0.6) hospital admission days. The mean total cost of CD over 6 months was $1,255.80 (range $0-$63,320.20; median $639.80). The largest single cost driver was the number of hospital admission days. CONCLUSIONS: The economic impact of CD-related health care resource use should not be overlooked when assessing disease burden. OBJECTIVES:The economic burden of Multiple Sclerosis (MS) on society and the individuals concerned is not known. Documenting such costs is essential for several reasons: costs of illness is a key factor of optimal disease management policies, knowledge of cost is useful for allocating research and development. The aim of our study as the first pharmacoeconomic investigation in Iran was to estimate the costs of multiple sclerosis according to severity of disease. METHODS: Total, direct and indirect costs were compared in 160 patients divided into three groups categorized by disease severity: stage I Expanded Disability Status Scale (EDSS Ͻ2.5), stage II (EDSS 3-4.5) and stage III (EDSS Ͼ5).The majority of these patients (94%) developed relapsing-remitting MS.A minority of the patients (0.2-4 %) developed secondary progressive and primary progressive MS. Cost evaluation was performed from the societal perspective and covered the one-year period. The study was carried out at the Division of Neurology at Ghaem Hospital and MS association in Mashhad in northeast of Iran and was approved by the local ethics committee. RESULTS: The mean total cost/patient for one year was estimated at $27,095, $27,997and $31,662 for stage I, II and III, respectively. Both direct and indirect costs increased with MS progression. For indirect cost the main item was productivity loss. The mean extra medicine (treatments for MS symptoms and adverse effects of medications) cost/patient for one year was calculated at $19,036. CONCLUSIONS: This study confirms that MS represents a high economic burden to patients and society, with direct costs greatly exceeding indirect costs. As costs increase with disease progression, treatment efforts should focus on patients in t...