Cost-effectiveness of modified diagnostic strategy to safely rule-out pulmonary embolism in the emergency department: a non-inferiority cluster crossover randomized trial (MODIGLIA-NI)

Background: The aim of this trial-based economic evaluation was to assess the incremental costs and cost-effectiveness of the modified diagnostic strategy combining the YEARS rule and age-adjusted D-dimer threshold compared with the control (which used the age-adjusted D-dimer threshold only) for the diagnosis of pulmonary embolism (PE) in the Emergency Department (ED).

Methods: Economic evaluation from a healthcare system perspective alongside a non-inferiority, crossover, and cluster-randomized trial conducted in 16 EDs in France and two in Spain with three months of follow-up. The primary endpoint was the additional cost of a patient without failure of the diagnostic strategy, defined as venous thromboembolism (VTE) diagnosis at 3months after exclusion of PE during the initial ED visit. Mean differences in 3-month failure and costs were estimated using separate generalized linear-regression mixed models, adjusted for strategy type, period, and the interaction between strategy and period as fixed effects and the hospital as a random effect. The incremental cost-effectiveness ratio (ICER) was obtained by dividing the incremental costs by the incremental frequency of VTE.

Results: Of the 1,414 included patients, 1,217 (86%) were analyzed in the per-protocol analysis (648 in the intervention group and 623 in the control group). At three months, there were no statistically significant differences in total costs (€-46; 95% CI: €-93 to €0.2), and the failure rate was non inferior in the intervention group (-0.64%, one-sided 97.5% CI: -∞ to 0.21%, non-inferiority margin 1.5%) between groups. The point estimate of the incremental cost-effectiveness ratio (ICER) indicating that each undetected VTE averted in the intervention group is associated with cost savings of €7,142 in comparison with the control group. There was a 93% probability that the intervention was dominant. Similar results were found in the as randomized population.

Conclusions: Given the observed cost decrease of borderline significance, and according to the 95% confidence ellipses, the intervention strategy has a potential to lead to cost savings as a result of a reduction in the use of chest imaging and of the number of undetected VTE averted. Policy-makers should investigate how these monetary benefits can be distributed across stakeholders.

Clinicaltrials: Trial registration number ClinicalTrials.gov Identifier: NCT04032769; July 25, 2019.