10 Decision analysis modelling of diagnostic strategies for suspected pulmonary embolism in pregnancy: the DiPEP economic evaluation
Using diagnostic imaging for suspected pulmonary embolism (PE) in pregnancy involves weighing the benefits, harms and costs of different approaches to selecting women for imaging.Objectives
To estimate the effectiveness of diagnostic strategies for PE in pregnancy and postpartum, in terms of adverse outcomes from venous thromboembolism, bleeding and radiation exposure, and cost effectiveness, measured as the incremental cost per quality-adjusted life year (QALY).Methods
Decision-analysis modelling was used to estimate costs incurred and expected outcomes from thromboembolism, bleeding and radiation exposure if a hypothetical cohort of pregnant or postpartum women based on the Diagnosis of PE in Pregnancy (DiPEP) study population were investigated for suspected PE using different strategies, including no imaging, selective imaging based on a clinical decision rule and imaging for all. Outcomes were modelled to estimate the quality-adjusted life years (QALYs) accrued by each strategy and the incremental cost per QALY gained by each strategy compared to the next most effective alternative. Threshold analysis explored the parameters required for a hypothetical clinical decision rule to be cost-effective.Results
Decision analysis showed that a nonselective strategy of scanning all women with suspected PE accrued more QALYs and incurred fewer costs than any selective strategy based on a clinical decision rule and was therefore the dominant strategy. This finding was robust in sensitivity analysis and scenario analysis exploring assumptions in the model. Threshold analysis showed that a clinical decision rule to select women for imaging would need to have sensitivity exceeding 97.5% to be cost-effective compared to nonselective use of scanning.Conclusion
There is little potential for selective imaging based on a clinical decision rule to be cost-effective compared to a strategy of nonselective imaging for all women with suspected PE in pregnancy and postpartum.