Potential of an age adjusted D-dimer cut-off value to improve the exclusion of pulmonary embolism in older patients: a retrospective analysis of three large cohorts

Abstract

Objectives In older patients, the the D-dimer test for pulmonary embolism has reduced specificity and is therefore less useful. In this study a new, age dependent cut-off value for the test was devised and its usefulness with older patients assessed. Design Retrospective multicentre cohort study. Setting General and teaching hospitals in Belgium, France, the Netherlands, and Switzerland. Patients 5132 consecutive patients with clinically suspected pulmonary embolism. Intervention Development of a new D-dimer cut-off point in patients aged >50 years in a derivation set (data from two multicentre cohort studies), based on receiver operating characteristics (ROC) curves. This cut-off value was then validated with two independent validation datasets. Main outcome measures The proportion of patients in the validation cohorts with a negative D-dimer test, the proportion in whom pulmonary embolism could be excluded, and the false negative rates. Results The new D-dimer cut-off value was defined as (patient's age×10) μg/l in patients aged >50. In 1331 patients in the derivation set with an "unlikely" score from clinical probability assessment, pulmonary embolism could be excluded in 42% with the new cut-off value versus 36% with the old cut-off value (<500 μg/l). In the two validation sets, the increase in the proportion of patients with a D-dimer below the new cut-off value compared with the old value was 5% and 6%. This absolute increase was largest among patients aged > 70 years, ranging from 13% to 16% in the three datasets. The failure rates (all ages) were 0.2% (95% CI 0% to 1.0%) in the derivation set and 0.6% (0.3% to 1.3%) and 0.3% (0.1% to 1.1%) in the two validation sets. Conclusions The age adjusted D-dimer cut-off point, combined with clinical probability, greatly increased the proportion of older patients in whom pulmonary embolism could be safely excluded.

Computed tomography pulmonary angiography is overused to diagnose pulmonary embolism in the emergency department of academic community hospital

“…Despite the high diagnostic accuracy of CTPA, less than 10% of the scans done to diagnose PE in the USA are positive, compared to a rate of 30% in European countries [3,7–10]. Moreover, CTPA comes with a high risk from exposure to ionizing radiation as well as risk from contrast-induced nephropathy [11,12].…”

D-Dimer Assays in Diagnosis and Management of Thrombotic and Bleeding Disorders

“…62 An age-dependent D-dimer cutoff value, calculated by multiplying the age of the patient by 10 in those older than 50 years (e.g., the D-dimer cutoff value for a patient 65 years of age would be 650 μg FEU/L instead of the conventional 500 μg FEU/L), has been proposed for use in older patients with suspected VTE. This age-specific cut-point has been shown in retrospective analyses to substantially increase the proportion of elderly patients in whom the diagnosis of PE 63 and DVT 64 can be safely excluded. However, before this strategy is accepted into clinical practice, it is necessary to prospectively validate it in a diagnostic management study with patient's follow-up.…”

Using an age-dependent D-dimer cut-off value increases the number of older patients in whom deep vein thrombosis can be safely excluded

“…6,8 Recently, a new age-adjusted D-dimer cut-off value was derived and retrospectively validated in patients with suspected PE older than 50 year of age. 9 It was shown to increase the proportion of older patients in whom the diagnosis could be excluded, without compromising safety. 9 The new age-adjusted D-dimer cut-off value is calculated by multiplying the patient's age by 10 in patients older than 50 years.…”