Written by Bo Stubblefield
In the diagnosis of deep venous thrombosis (DVT), both age-adjusted D-dimer and D-dimer adjusted by clinical pre-test probability (CPTP) were found to be similar (read: not statistically different) in sensitivity, specificity, negative predictive value (NPV), and utility* in this meta-analysis.
Why does this matter?
Kearon et. al. recently published the PEGeD study in NEJM on the diagnosis of pulmonary embolism (PE) using D-dimer adjusted to clinical pretest probability. They compared both the age-adjusted and YEARS strategies to adjusting the D-dimer to CPTP and found that chest imagining was reduced using the CPTP strategy in patients with a low clinical pretest probability. Notably, the reduction in imaging for PE was greatest when the CPTP strategy was compared to the age-adjusted strategy. So why not conduct a meta-analysis comparing age-adjusted D-dimer and CPTP-adjusted D-dimer head-to-head for the diagnosis of DVT?
Adjust by age or adjust by CPTP, but you gotsta adjust!
The authors conducted a meta-analysis utilizing an established individual patient database to compare the sensitivity, specificity, NPV, and utility of D-dimer interpretation between the age-adjusted and CPTP strategies. 2554 patients were included in the analysis over four studies containing substantial heterogeneity between the individual studies. Overall, there was no statistically significant difference in the pooled diagnostic indices between strategies and insufficient evidence to suggest one strategy was superior to the other:
These findings reconfirmed that both CPTP-adjusted and age-adjusted D-dimer interpretation had a substantially higher utility*, with similar good NPV compared to the unadjusted or standard D-dimer interpretation (<500ng/mL).
*Utility = proportion of patients with negative D-dimer
Check out our recent JournalFeed on the PEGeD study published in NEJM on the Dx of PE with D-dimer adjusted to clinical pretest probability. Here is a second helping from the PEGeD study: REBEL EM, The Bottom Line, EM Lit of Note
Clinical pre-test probability adjusted versus age-adjusted D-dimer interpretation strategy for DVT diagnosis: A diagnostic individual patient data meta-analysis. J Thromb Haemost. 2019 Dec 23. doi: 10.1111/jth.14718.
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Reviewed by Clay Smith