[Objectives] Self-care with over-the-counter (OTC) by non-steroidal anti-inflammatory drugs (NSAIDs), Chinese Medicines and whatever, is widely used for pelvic pain relief in dysmenorrhea patients in Japan; however, guideline-recommended intervention consists based on Oral Contraceptives (OC) and low-dose estrogen and progestin hormonal combinations (LEP). This study aims to assess the cost-effectiveness of OC/LEP for the prevention of disease progression and/or ovarian cancer, compared to no use, in Japan.

[Methods] A Markov model with a 43-year time horizon and annual cycles was constructed. The model consisted of six major health states with three sub-medical and cancer-related states. The analyses were conducted from healthcare only as well as all direct cost (inclusive of OTC) payer’s perspectives. Transition probabilities among health and medical states were derived from literature review. Disease-associated costs, such as inpatient, outpatient, surgery, and prescription, and OTC costs were input. Utility measures were collected prospectively from patients with stage I-IV endometriosis using a visual analogue scale. An annual discount rate at 2% was considered. Sensitivity analyses were performed to examine the impact of uncertainties.

[Results] Base case outcomes indicated that intervention would be superior to no use when considering all costs (cost-saving by approximately 270 K JPY) with 0.3 incremental quality-adjusted life-years (QALYs) gained. From the payer’s perspective, intervention would be more cost-effective than no use, as the incremental cost-effectiveness ratio yielded 2.2 M JPY per QALY gained. A tornado diagram depicting the deterministic sensitivity analysis was constructed, and robustness was confirmed. A probabilistic analysis resulting from 10,000-time Monte Carlo simulations demonstrated efficiency at Willingness-To-Pay thresholds of 5 M JPY in more than 90% of the iteration.

[Conclusion] Our analysis demonstrated that, in Japan, OC/LEP would be more cost-effective than no use in preventing disease progression and/or cancer for patients with dysmenorrhea.