D‐dimer testing is useful to exclude deep vein thrombosis in elderly outpatients

Summary

Background: Deep vein thrombosis (DVT) can be safely and reliably excluded in patients with a low clinical probability and a negative D‐dimer result but the accuracy and utility of such a strategy is unclear in elderly patients. Objectives: We sough to compare the performance of the Wells pretest probability (PTP) model and D‐dimer testing between patients of different age groups and to examine the utility of the two PTP model classification schemes (low/moderate/high vs. unlikely/likely) in excluding DVT in elderly outpatients. Patients/Methods: Pooled analysis of databases from three prospective diagnostic studies evaluating consecutive outpatients with suspected DVT. Results: A total of 2696 patients were evaluated. DVT was diagnosed in 400 (15%) patients overall and in 50 out of 325 (15.5%) patients ≥ 60 years old. The PTP distribution and the prevalence of DVT in each PTP category were similar among the different age groups. The negative predictive values of a low or unlikely PTP score in combination with a negative D‐dimer result were 99% for all groups. A negative D‐dimer in combination with a low or unlikely PTP excluded 21.7% and 31% of patients ≥ 80 years old, respectively. Conclusions: The combination of a low or unlikely PTP with a negative D‐dimer result can effectively and safely exclude DVT in a significant proportion of elderly outpatients. However, this clinical prediction rule needs to be prospectively validated with different D‐dimer assays in this specific population.