The age-adjusted D-dimer cut-off value increased the proportion of patients with non-high clinical probability in whom deep vein thrombosis could be excluded to 51% compared to 42% with the conventional cut-off.
Cohort (n=2,818)
Yes
Does an age-adjusted D-dimer cut-off increase the proportion of older patients in whom deep vein thrombosis can be safely excluded compared to a conventional cut-off?
Using an age-adjusted D-dimer cut-off safely increases the proportion of older patients in whom deep vein thrombosis can be excluded without increasing the rate of missed diagnoses.
Effect estimate: Absolute increase 8.6% (95% CI 7.3-10)
Absolute Event Rate: 51% vs 42%
BACKGROUND: D-dimer testing to rule out deep vein thrombosis is less useful in older patients because of a lower specificity. An age-adjusted D-dimer cut-off value increased the proportion of older patients (>50 years) in whom pulmonary embolism could be excluded. We retrospectively validated the efficacy of this cut-off combined with clinical probability for the exclusion of deep vein thrombosis. DESIGN AND METHODS: Five management study cohorts of 2818 consecutive outpatients with suspected deep vein thrombosis were used. Patients with non-high or unlikely probability of deep vein thrombosis were included in the analysis; four different D-dimer tests were used. The proportion of patients with a normal D-dimer test and the failure rates were calculated using the conventional (500 μg/L) and the age-adjusted D-dimer cut-off (patient's age x 10 μg/L in patients >50 years). RESULTS: In 1672 patients with non-high probability, deep vein thrombosis could be excluded in 850 (51%) patients with the age-adjusted cut-off value versus 707 (42%) patients with the conventional cut-off value. The failure rates were 7 (0.8; 95% confidence interval 0.3-1.7%) for the age-adjusted cut-off value and 5 (0.7%, 0.2-1.6%) for the conventional cut-off value. The absolute increase in patients in whom deep vein thrombosis could be ruled out using the age-adjusted cut-off value was largest in patients >70 years: 19% among patients with non-high probability. CONCLUSIONS: The age-adjusted cut-off of the D-dimer combined with clinical probability greatly increases the proportion of older patients in whom deep vein thrombosis can be safely excluded.
Douma et al. (Tue,) conducted a cohort in Suspected deep vein thrombosis (DVT) (n=2,818). Age-adjusted D-dimer cut-off value (age x 10 mg/L for >50 years) vs. Conventional D-dimer cut-off value (500 mg/L) was evaluated on Proportion of patients with non-high clinical probability in whom DVT could be excluded (Absolute increase 8.6%, 95% CI 7.3-10). The age-adjusted D-dimer cut-off value increased the proportion of patients with non-high clinical probability in whom deep vein thrombosis could be excluded to 51% compared to 42% with the conventional cut-off.