Discussion
pulmonary embolism, VTE
PULMONARY EMBOLISM
In this within-trial economic evaluation of the use of the YEARS criteria combined with the age-adjusted D-dimer threshold compared to the standard diagnostic strategy to rule out pulmonary embolism in the emergency department, we found a high probability that combining YEARS and age-adjusted D-dimers is less costly and non inferior to the control with age-adjusted D-dimers alone. The majority of bootstrap replications (93% of cases) in the CE planes showed that intervention strategy had a high probability of being a dominant strategy, both cost saving and outcome improving.Our results show that the point estimates of cost and effect-difference between the intervention group and the control group was not statistically significant, although total costs and failure rate were lower in the intervention strategy than in the control strategy. The strict protocol for patient management in the ED made it unlikely to allow large differences in resource use, although the use of chest imaging was 9% lower in the intervention strategy. The largest contributor to the cost difference was the hospital admission following ED workup, but it only amounted to 30€ because of the low admission rate. Both strategies were successful at ruling out PE without false negatives, which was an ethical requirement of the protocol and explains the small difference in re admission rates and costs.In addition, the sample size was based on the primary outcome of the presence of VTE at 3 months, and therefore was insufficiently powerful to detect relevant cost differences. However, the health economics literature is clear that the decision to estimate incremental cost-effectiveness should not be based on separate and sequential hypothesis tests concerning cost and effect differences, but should instead consider the joint density of cost and effect differences. The results here bear out this recommendation, showing that modest cost and effect differences considered jointly produce a high probability that the intervention will be less costly and more effective.To our knowledge, our study is the first formal cost-effectiveness evaluation of a strategy that combines the YEARS rule and the age-adjusted D-dimer cutoff. However, a number of previous cost-effectiveness analyses of diagnostic strategies including D-dimer to exclude PE have been published. A systematic review in 2022 [These results were derived from a pragmatic trial with a large sample size and 18 participating hospitals, which allowed prospective collection of relevant cost and effect data, and enabled the evaluation of the intervention’s cost-effectiveness. The randomization ensured a high internal validity of the results. The pragmatic design, the large number of participating centers with broad inclusion criteria and adherence to current guidelines in the control group suggest that the external validity is also good. Although the cost are based on French data, they would be close to those in other Western European countries, albeit not in the USA.This study presents several limitations, which include the limitations of the trial listed in the princeps publication [