RESUMO
BACKGROUND: Persistent pregnancies of unknown location are defined by abnormally trending serum human chorionic gonadotropin with nondiagnostic ultrasound. There is no consensus on optimal management. OBJECTIVE: This study aimed to assess the cost-effectiveness of 3 primary management strategies for persistent pregnancies of unknown location: (1) expectant management, (2) empirical 2-dose methotrexate, and (3) uterine evacuation followed by methotrexate, if indicated. STUDY DESIGN: This was a prospective economic evaluation performed concurrently with the Expectant versus Active Management for Treatment of Persistent Pregnancies of Unknown Location multicenter randomized trial that was conducted from July 2014 to June 2019. Participants were randomized 1:1:1 to expectant management, 2-dose methotrexate, or uterine evacuation. The analysis was from the healthcare sector perspective with a 6-week time horizon after randomization. Costs were expressed in 2018 US dollars. Effectiveness was measured in quality-adjusted life years and the rate of salpingectomy. Incremental cost-effectiveness ratios and cost-effectiveness acceptability curves were generated. Sensitivity analyses were performed to assess the robustness of the analysis. RESULTS: Methotrexate had the lowest mean cost ($875), followed by expectant management ($1085) and uterine evacuation ($1902) (P=.001). Expectant management had the highest mean quality-adjusted life years (0.1043), followed by methotrexate (0.1031) and uterine evacuation (0.0992) (P=.0001). The salpingectomy rate was higher for expectant management than for methotrexate (9.4% vs 1.2%, respectively; P=.02) and for expectant management than for uterine evacuation (9.4% vs 8.1%, respectively; P=.04). Uterine evacuation, with the highest costs and the lowest quality-adjusted life years, was dominated by both expectant management and methotrexate. In the base case analysis, expectant management was not cost-effective compared with methotrexate at a willingness to pay of $150,000 per quality-adjusted life year given an incremental cost-effectiveness ratio of $175,083 per quality-adjusted life year gained (95% confidence interval, -$1,666,825 to $2,676,375). Threshold analysis demonstrated that methotrexate administration would have to cost $214 (an increase of $16 or 8%) to favor expectant management. Moreover, expectant management would be favorable in lower-risk patient populations with rates of laparoscopic surgical management for ectopic pregnancy not exceeding 4% of pregnancies of unknown location. Based on the cost-effectiveness acceptability curves, the probability of expectant management being cost-effective compared with methotrexate at a willingness to pay of $150,000 per quality-adjusted life year gained was 50%. The results were dependent on the cost of surgical intervention and the expected rate of methotrexate failure. CONCLUSION: The management of pregnancies of unknown location with a 2-dose methotrexate protocol may be cost-effective compared with expectant management and uterine evacuation. Although uterine evacuation was dominated, expectant management vs methotrexate results were sensitive to modest changes in treatment costs of both methotrexate and surgical management.