D-Dimer Levels Have Limited Value in Identifying Pulmonary Embolism in COVID-19

D-dimer levels are higher among patients hospitalized with COVID-19 with pulmonary thromboembolism (PTE) vs those without PTE. Additionally, D-dimer levels in patients with COVID-19 have modest discriminative power to identify PTE; thus, using D-dimer to exclude PTE in these patients may be of limited clinical value, according to study findings published in The Brazilian Journal of Infectious Diseases.

There is uncertainty as to whether measuring D-dimer levels among patients with COVID-19 can facilitate identification of PTE. Researchers sought to determine whether D-dimer levels could be used to rule out PTE in patients with COVID-19 and to assess clinical and laboratory associations between D-dimer levels and PTE on computed tomography pulmonary angiogram (CTPA).

The investigators conducted a retrospective study that included 697 adult patients with severe acute respiratory syndrome from COVID-19 (confirmed on positive RT-PCR or antigen testing and at least 2 recognized symptoms) who presented at Hospital de Clinicas de Porto Alegre, a tertiary care hospital in Porto Alegre, Brazil, from March 2020 to May 2021.

Patients underwent CTPA and had D-dimer collected within 48 hours from CTPA. Among these patients (age 59±20.5 years; 45.2% women) with COVID-19 and suspected PTE, 71.5% needed intensive care admission and 35.6% died during hospitalization. Researchers noted nearly a third of these patients had radiographic evidence of PTE (54% segmental, 19.6% lobar, 14.1% subsegmental, 12.3% proximal). The researchers further noted no significant statistical differences in sex, body mass index, age, and comorbidities between study participants with and without PTE.

The study found higher D-dimer levels in patients with PTE vs those without PTE (9.1 9 [range, 3.9-20.0] vs 2.3 [range, 1.2-5.1]; P <.001). With a D-dimer cutoff of 0.5 μg/mL or above, sensitivity was 98.2% and specificity was 5.7%. The researchers noted that 99.1% of participants with PTE had increased D-dimer values, with the 0.3 μg/mL threshold associated with 100% of sensitivity for the presence of PTE. The receiver operating characteristic curve revealed D-dimer had moderate discriminative power to detect PTE.

The investigators also found a higher independent association between mortality and the presence of PTE vs no PTE (42.5% vs 32.3%; P =.038).

Study limitations include the retrospective study design, selection bias, difficulty controlling for confounders, the receipt of heparin at prophylactic or therapeutic doses in the majority of patients, and the lack of evaluation for concomitant types of thromboembolism.

Researchers concluded that “D-dimer levels are higher among COVID-19 hospitalized patients with PTE as compared to those without PTE and have moderate discriminative power to detect PTE, but its use to exclude PTE in this population may have limited clinical utility.”

This article originally appeared on Pulmonology Advisor