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Meta-Analysis
. 2021 Jan-Dec:27:1076029621996471.
doi: 10.1177/1076029621996471.

Pulmonary Embolism Does Not Have an Unusually High Incidence Among Hospitalized COVID19 Patients

Nicolas Gallastegui  1 , Jenny Y Zhou  1 , Annette von Drygalski  1   2 , Richard F W Barnes  1 , Timothy M Fernandes  3 , Timothy A Morris  3
Affiliations
Meta-Analysis

Pulmonary Embolism Does Not Have an Unusually High Incidence Among Hospitalized COVID19 Patients

Nicolas Gallastegui et al. Clin Appl Thromb Hemost. 2021 Jan-Dec.

Abstract

Introduction: Acute respiratory illnesses from COVID19 infection are increasing globally. Reports from earlier in the pandemic suggested that patients hospitalized for COVID19 are at particularly high risk for pulmonary embolism (PE). To estimate the incidences of PE during hospitalization for COVID19, we performed a rigorous systematic review of published literature.

Methods: We searched for case series, cohort studies and clinical trials from December 1, 2019 to July 13, 2020 that reported the incidence of PE among consecutive patients who were hospitalized for COVID19 in ICUs and in non-ICU hospital wards. To reflect the general population of hospitalized COVID19 patients, we excluded studies in which subject enrollment was linked to the clinical suspicion for venous thromboembolism (VTE).

Results: Fifty-seven studies were included in the analysis. The combined random effects estimate of PE incidence among all hospitalized COVID19 patients was 7.1% (95% CI: 5.2%, 9.1%). Studies with larger sample sizes reported significantly lower PE incidences than smaller studies (r2 = 0.161, p = 0.036). The PE incidence among studies that included 400 or more patients was 3.0% (95% CI: 1.7%, 4.6%). Among COVID19 patients admitted to ICUs, the combined estimated PE incidence was 13.7% (95% CI: 8.0%, 20.6%). The incidence of ICU-related PE also decreased as the study sample sizes increased. The single largest COVID19 ICU study (n = 2215) disclosed a PE incidence of 2.3% (95% CI: 1.7%, 3.0%).

Conclusion: PE incidences among hospitalized COVID19 patients are much lower than has been previously postulated based on smaller, often biased study reports. The incidence of "microthrombosis," leading to occlusion of microscopic blood vessels, remains unknown.

Keywords: COVID-19; SARS-COV-2; deep venous thrombosis; pulmonary embolism; thromboembolism.

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Conflict of interest statement

Declaration of Conflicting Interests: The author(s) declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article: Dr Fernandes reports no disclosures related to submitted works but has received consulting fees from Bayer Pharmaceuticals, Arena Pharmaceuticals, Bristol-Myers-Squibb and research funds from Janssen and United Therapeutics. Dr Morris reports no disclosures related to submitted works but has received grants from Bayer, grants from CHEST Foundation, personal fees from Bayer, personal fees from Pfizer, personal fees from Faegre, personal fees from Inari, outside the submitted work. Dr von Drygalski reports no disclosures related to submitted works but received fees from Biomarin, Bioverativ/Sanofi-Genzyme, Novo Nordisk, Pfizer, Takeda and Uniqure for participation in Industry sponsored Education events and Advisory Boards, and research support from Pfizer and Bioverativ/Sanofi. She is Co-Founder and a member of the Board of Directors of Hematherix Inc and holds a patent for a superFVa. She is the inventor of the Joint Activity and Damage Examination (JADE) Ultrasound measurement tool, which is copyrighted and is commercialized by the University of California San Diego. Drs Barnes, Zhou and Gallastegui Crestani report no potential conflicts of interest.

Figures

Figure 1.
Figure 1.
Study selection. Flow diagram of search and selection of published papers.
Figure 2.
Figure 2.
The incidence of PE against the number of hospitalized COVID19 patients at risk. The size of each bubble is proportional to the study weight (1/variance), which reflects the precision of the study. Panel A. Estimated incidence of PE incidence decreases with study sample size. r2 = 0.161, p = 0.036. Panel B. PE incidence decreases with study sample size and varies with clinical location (white circles and dotted line—non-ICU wards, black circles and dashed line—ICU, grey circles and solid line—combination of ICU and non-ICU wards). r2 = 0.351, p = 0.001. Panel C. PE incidence decreases with study sample size and varies with geographic location (white circles and dotted line—Asia, black circles and dashed line—Europe, grey circles and solid line—USA). Middle East and multinational were too few to be included in the regression model. r2 = 0.550, p < 0.001. Panel D. PE incidence plotted against study size but does not vary with anticoagulation regimen (white circles and dotted line—at least 95% of patients were on standard prophylaxis regimens, black circles and dashed line—mixed prophylaxis regimens, grey circles and solid line—not specified). r2 = 0.198, p = 0.040.
Figure 3.
Figure 3.
Incidence of PE among patients hospitalized for COVID19. The reported incidences of PE among the included studies are represented by Forest plots. Panel A.  The reported incidences of PE among all patients hospitalized for COVID19.  Panel B.  PE incidences among patients admitted to ICUs for COVID19.
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