Vasa previa screening strategies: decision and cost-effectiveness analysis

Objective: To perform a decision and cost-effectiveness analysis comparing four screening strategies for the antenatal diagnosis of vasa previa in singleton pregnancies. Methods: A decision-analytic model was constructed comparing vasa previa screening strategies. Published probabilities and costs were applied to four transvaginal screening scenarios that were carried out at the time of mid-trimester ultrasound: no screening, ultrasound-indicated screening, screening only pregnancies conceived by in-vitro fertilization (IVF) and universal screening. Ultrasound-indicated screening was defined as performing transvaginal ultrasound at the time of the routine anatomy ultrasound scan in response to one of the following sonographic findings associated with an increased risk of vasa previa: low-lying placenta, marginal or velamentous cord insertion or bilobed or succenturiate lobed placenta. The primary outcome was cost per quality-adjusted life year (QALY) in US$. The analysis was performed from a healthcare system perspective with a willingness-to-pay threshold of $100 000 per QALY selected. One-way and multivariate sensitivity analysis (Monte-Carlo simulation) was performed. Results: This decision-analytic model demonstrated that screening pregnancies conceived by IVF was the most cost-effective strategy, with an incremental cost effectiveness ratio (ICER) of $29186.50/QALY. Ultrasound-indicated screening was the second most cost-effective, with an ICER of $56096.77/QALY. These data were robust to all one-way and multivariate sensitivity analyses performed. Conclusions: Within the baseline assumptions, transvaginal ultrasound screening for vasa previa appears to be most cost-effective when performed among IVF pregnancies. However, both IVF and ultrasound-indicated screening strategies fall within contemporary willingness-to-pay thresholds, suggesting that both strategies may be appropriate to apply in clinical practice.