ABSTRACT: INTRODUCTION:The prevalence of endometriosis and the need for treatment in the USA has led to the need to explore the contemporary cost burden associated with the disease. This retrospective cohort study compared direct and indirect healthcare costs in patients with endometriosis to a control group without endometriosis. METHODS:Women aged 18-49 years with endometriosis (date of initial diagnosis = index date) were identified in the Truven Health MarketScan® Commercial database between 2010 and 2014 and female control patients without endometriosis were matched by age and index year. The following outcomes were compared: healthcare resource utilization (HRU) during the 12-month pre- and post-index periods (including inpatient admissions, pharmacy claims, emergency room visits, physician office visits, and obstetrics/gynecology visits), annual direct (medical and pharmacy) and indirect (absenteeism, short-term disability, and long-term disability) healthcare costs during the 12-month post-index period (in 2014 US$). Multivariate analyses were conducted to estimate annual total direct and indirect costs, controlling for demographics, pre-index clinical characteristics, and pre-index healthcare costs. RESULTS:Overall, 113,506 endometriosis patients and 927,599 controls were included. Endometriosis patients had significantly higher HRU during both the pre- and post-index periods compared to controls (p < 0.0001, all categories of HRU). Approximately two-thirds of endometriosis patients underwent an endometriosis-related surgical procedure (including laparotomy, laparoscopy, hysterectomy, oophorectomy, and other excision/ablation procedures) in the first 12 months post-index. Mean annual total adjusted direct costs per endometriosis patient during the 12-month post-index period was over three times higher than that for a non-endometriosis control [$16,573 (standard deviation (SD) = $21,336) vs. $4733 (SD = $14,833); p < 0.005]. On average, incremental direct and indirect 12-month costs per endometriosis patient were $10,002 and $2132 compared to their matched controls (p < 0.005). CONCLUSIONS:Endometriosis patients incurred significantly higher direct and indirect healthcare costs than non-endometriosis patients. FUNDING:AbbVie Inc.