Diagnostic Accuracy and Financial Implications of Age-Adjusted D-Dimer Strategies for the Diagnosis of Deep Venous Thrombosis in the Emergency Department

Diagnostic Accuracy of Multiple D-Dimer Cutoff Thresholds and Other Clinically Applicable Biomarkers for the Detection and Radiographic Evaluation of Pulmonary Embolism

Background: Diagnostic work-up of pulmonary embolism (PE) remains a challenge. Methods: We retrospectively studied all patients referred for computed tomography pulmonary angiography (CTPA) with suspicion of PE during a 12-month period (2018). The diagnostic accuracy of different D-dimer (Dd) cutoff thresholds for ruling out PE was evaluated. Furthermore, the association of Dd and red cell distribution width (RDW) with embolus location, CTPA findings, and patient outcome was recorded. Results: One thousand seventeen (n = 1017) patients were finally analyzed (mean age: 64.6 years (SD = 11.8), males: 549 (54%)). PE incidence was 18.7%. Central and bilateral embolism was present in 44.7% and 59.5%, respectively. Sensitivity and specificity for conventional and age-adjusted Dd cutoff was 98.2%, 7.9%, and 98.2%, 13.1%, respectively. A cutoff threshold (2.1 mg/L) with the best (64.4%) specificity was identified based on Receiver Operating Characteristics analysis. Moreover, a novel proposed Dd cutoff (0.74 mg/L) emerged with increased specificity (20.5%) and equal sensitivity (97%) compared to 0.5 mg/L, characterized by concurrent reduction (17.2%) in the number of performed CTPAs. Consolidation/atelectasis and unilateral pleural effusion were significantly associated with PE (p < 0.05, respectively). Patients with consolidation/atelectasis or intrapulmonary nodule(s)/mass on CTPA exhibited significantly greater median Dd values compared to patients without the aforementioned findings (2.34, (IQR 1.29−4.22) vs. 1.59, (IQR 0.81−2.96), and 2.39, (IQR 1.45−4.45) vs. 1.66, (IQR 0.84−3.12), p < 0.001, respectively). RDW was significantly greater in patients who died during hospitalization (p = 0.012). Conclusions: Age-adjusted Dd increased diagnostic accuracy of Dd testing without significantly decreasing the need for imaging. The proposed Dd value (0.74 mg/L) showed promise towards reducing considerably the need of CTPA. Multiple radiographic findings have been associated with increased Dd values in our study.

Cost-effectiveness of diagnostic strategies for venous thromboembolism: a systematic review

Guideline developers consider cost-effectiveness evidence in decision making to determine value for money. This consideration in the guideline development process can be informed either by formal and dedicated economic evaluations or by systematic reviews of existing studies. To inform the American Society of Hematology guideline on the diagnosis of venous thromboembolism (VTE), we conducted a systematic review focused on the cost-effectiveness of diagnostic strategies for VTE within the guideline scope. We systematically searched Medline (Ovid), Embase (Ovid), National Health Service Economic Evaluation Database, and the Cost-effectiveness Analysis Registry; summarized; and critically appraised the economic evidence on diagnostic strategies for VTE. We identified 49 studies that met our inclusion criteria, with 26 on pulmonary embolism (PE) and 24 on deep vein thrombosis (DVT). For the diagnosis of PE, strategies including d-dimer to exclude PE were cost-effective compared with strategies without d-dimer testing. The cost-effectiveness of computed tomography pulmonary angiogram (CTPA) in relation to ventilation-perfusion (V/Q) scan was inconclusive. CTPA or V/Q scan following ultrasound or d-dimer results could be cost-effective or even cost saving. For DVT, studies supporting strategies with d-dimer and/or ultrasound were cost-effective, supporting the recommendation that for patients at low (unlikely) VTE risk, using d-dimer as the initial test reduces the need for diagnostic imaging. Our systematic review informed the American Society of Hematology guideline recommendations about d-dimer, V/Q scan and CTPA for PE diagnosis, and d-dimer and ultrasound for DVT diagnosis.

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

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.

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Key Words

• biomarker
• cost-benefit analysis
• diagnosis
• fibrin fragment D
• pulmonary embolism

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MESH Headings

• Angiography
• Cost-Benefit Analysis
• Fibrin Fibrinogen Degradation Products
• Humans
• Pulmonary Embolism/diagnosis

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Affiliation(s)

Marc Blondon Division of Angiology and Haemostasis, Faculty of Medicine and Geneva University Hospitals, Geneva, Switzerland
Gregoire Le Gal Department of Medicine, Ottawa Hospital Research Institute, University of Ottawa, ON, Canada
Guy Meyer Department of Respiratory Disease, Hôpital Européen Georges Pompidou, APHP, Paris, France Université Paris Descartes, Paris, France
Marc Righini Division of Angiology and Haemostasis, Faculty of Medicine and Geneva University Hospitals, Geneva, Switzerland
Helia Robert-Ebadi Division of Angiology and Haemostasis, Faculty of Medicine and Geneva University Hospitals, Geneva, Switzerland

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