Age-adjusted D-dimer cutoff for the diagnosis of pulmonary embolism: A cost-effectiveness analysis

Background In patients with suspected pulmonary embolism (PE) and a non-high pretest probability, the use of an age-adjusted D-dimer cutoff (AADD, <500 ng/mL up to 50 years, then <age x 10 ng/mL) was shown to further reduce the need for computed tomography pulmonary angiography while safely ruling out PE. Our objective was to evaluate its cost-effectiveness. Methods We created a decision tree to compare the use of the AADD with the standard D-dimer cutoff. The model included short-term venous thromboembolism-related events and long-term complications, their associated morbidity/mortality, and costs. Probabilities were derived from published literature and the ADJUST-PE study, and costs from US estimates. The time horizon was lifetime, with a health care system perspective. Results Using the AADD cutoff, compared with the standard cutoff, was associated with a loss of 0.0001 quality-adjusted life-years (QALY) and an average cost reduction of $33.4. The decremental cost-effectiveness ratio (DCER) was +$282 881/lost QALY (95% confidence interval from +$43 209/lost QALY to a dominant strategy). The probability that the use of the AADD cutoff was either dominant or gained >$200 000/lost QALY was 79.4%. In sensitivity analyses, the DCER became <+$200 000/lost QALY only if, among patients with D-dimer below the AADD cutoff, the mortality of an undiagnosed PE was >6% or the prevalence of PE was >0.6%. Conclusions The AADD cutoff results in a clinically nonsignificant decrease in QALY but important costs reductions. It is a decrementally cost-effective innovation, with a potential of cost savings of >$80 million per year for the United States health care system.