Optimizing resource allocation: Cost-effectiveness of specified D-dimer cut-offs in cancer patients with suspected venous thromboembolism

Abstract

An accurate diagnosis of venous thromboembolism (VTE) is crucial, given the potential for high mortality in undetected cases. Strategic D-dimer testing may aid in identifying low-risk patients, preventing overdiagnosis and reducing imaging costs. We conducted a retrospective, comparative analysis to assess the potential cost savings that could be achieved by adopting different approaches to determine the most effective D-dimer cut-off value in cancer patients with suspected VTE, compared to the commonly used rule-out cut-off level of 0.5 mg/L. The study included 526 patients (median age 65, IQR 55-75) with a confirmed cancer diagnosis who underwent D-dimer testing. Among these patients, the VTE prevalence was 29% (n = 152). Each diagnostic strategy's sensitivity, specificity, negative likelihood ratio (NLR), as well as positive likelihood ratio (PLR), and the proportion of patients exhibiting a negative D-dimer test result, were calculated. The diagnostic strategy that demonstrated the best balance between specificity, sensitivity, NLR, and PLR, utilized an inverse age-specific cut-off level for D-dimer [0.5 + (66-age) × 0.01 mg/L]. This method yielded a PLR of 2.9 at a very low NLR for the exclusion of VTE. We observed a significant cost reduction of 4.6% and 1.0% for PE and DVT, respectively. The utilization of an age-adjusted cut-off [patient's age × 0.01 mg/L] resulted in the highest cost savings, reaching 8.1% for PE and 3.4% for DVT. Using specified D-dimer cut-offs in the diagnosis of VTE could improve economics, considering the limited occurrence of confirmed cases among patients with suspected VTE.

Keywords: Cancer; Cost-effectiveness analysis; D-dimer; Deep vein thrombosis; Pulmonary embolism; Venous thromboembolism.

Fig. 1

Diagnostic algorithm for suspected DVT (first event) using compression ultrasonography, adapted according to current guidelines [1]. Pricings for CUS and D-dimer testing were taken from the German scale of fees for physicians (MFS) ⁵¹. Abbreviations: CUS, compression ultrasound; DVT, deep vein thrombosis; MFS, Medical fee schedule

Fig. 2

Diagnostic algorithm for suspected PE in hemodynamically stable patients, adapted according to current guidelines [1]. All prices were taken from the German scale of fees for physicians (MFS) ⁵¹. Abbreviations: CUS, compression ultrasound; CTPA, computed tomography pulmonary angiography; DVT, deep vein thrombosis; EchoCG, echocardiogram; MFS, Medical fee schedule; PE, pulmonary embolism; RH, right heart; sPESI, simplified Pulmonary Embolism Severity Index; VTE, venous thromboembolism; V/Q-scintigraphy, ventilation-perfusion scintigraphy