Endometriosis cost assessment (the EndoCost study): a cost-of-illness study protocol.

AIMS The EndoCost study aims to calculate the costs of endometriosis from a societal perspective. METHODS This multicentre, prevalence-based cost-of-illness analysis aggregates data on endometriosis costs and quality of life from a prospective hospital questionnaire and from both retrospective and prospective patient questionnaires. The EndoCost study comprises 12 representative tertiary care centres involved in the care of women with endometriosis in 10 countries. The sample includes patients with a laparoscopic and/or histological diagnosis of endometriosis and with at least 1 patient contact related to endometriosis during 2008. The EndoCost study measures direct healthcare costs (e.g. costs of medication, physician visits), direct non-healthcare costs (e.g. transportation costs), and indirect costs of productivity loss. Cost questions are developed specifically for the purpose of the EndoCost study. Quality of life is measured using the EuroQol-5D and relevant parts of the Global Study of Women's Health instruments. Both aggregate analyses and country-specific analyses are planned for total costs per patient. Costs are broken down into cost drivers and into the various payers that incur costs. CONCLUSIONS The cost estimates provided by the EndoCost cost-of-illness analysis may be used to justify the prioritisation of future research in endometriosis.