key: cord-0940125-y3iixkg9 authors: Wretborn, Jens; Jörg, Matthias; Benjaminsson Nyberg, Patrik; Wilhelms, Daniel B. title: Risk of venous thromboembolism in a Swedish healthcare system during the COVID‐19 pandemic: A retrospective cross‐sectional study date: 2021-09-01 journal: J Am Coll Emerg Physicians Open DOI: 10.1002/emp2.12530 sha: cb5490addfb95fa20dc60c05408c5f7b90310e12 doc_id: 940125 cord_uid: y3iixkg9 OBJECTIVE: The objective of this study was to investigate the risk and prevalence of venous thromboembolism (VTE) for patients undergoing a diagnostic test for VTE with confirmed COVID‐19 infection compared with patients with no COVID‐19 infection. METHODS: This was a retrospective cross‐sectional study of patients in an integrated healthcare system in Sweden, covering a population of 465,000, with a diagnostic test for VTE between March 1 and May 31 in the years 2015 to 2020. Risk for VTE with COVID‐19 was assessed by logistic regression, adjusting for baseline risk factors. RESULTS: A total of 8702 patients were included, and 88 of those patients tested positive on the severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) polymerase chain reaction test. A positive SARS‐CoV‐2 test did not increase the odds for VTE (odds ratio, 0.97; 95% confidence interval [CI], 0.55–1.74) and did not change when adjusting for sex, previous VTE, previous malignancy, Charlson score, hospital admission, intensive care, or ongoing treatment with anticoagulation (odds ratio, 0.72; 95% CI, 0.16–3.3). The prevalence of VTE was unchanged in 2020 compared with 2015 to 2019 (16.5% vs 16.1%, respectively), and there was no difference in VTE between the SARS‐CoV‐2 positive, negative, or untested groups in 2020 (15.9%, 17.6%, and 15.7%, respectively; P = 0.85). CONCLUSIONS: We found no increased prevalence of VTE in the general population compared with previous years and no increased risk of VTE in patients who were SARS‐CoV‐2 positive, suggesting that SARS‐CoV‐2 status should not influence VTE workup in the emergency department. The prevalence of VTE was high in patients with SARS‐CoV‐2 treated in the intensive care unit (ICU), where the suspicion for VTE should remain high. In the ongoing COVID-19 pandemic, reports have shown an increased risk of venous thromboembolism (VTE), including both pulmonary embolism (PE) and deep venous thrombosis (DVT), [1] [2] [3] [4] [5] and international guidelines recommend prophylactic anticoagulation for all hospitalized patients with COVID-19. 6 The majority of reports on VTE in COVID- 19 have been carried out in the intensive care unit (ICU) and show a prevalence of VTE of 20% to 30%. [1] [2] [3] This is higher than cohorts of non-selected ICU patients where the prevalence of VTE is closer to 10%. [7] [8] [9] [10] However, studies on ICU patients with severe sepsis and viral infections such as H1N1 influenza have shown a prevalence of VTE of 37% and 44%, respectively. 11, 12 The prevalence of VTE in hospitalized non-ICU patients with COVID-19 is 3% to 4%, [13] [14] [15] similar to studies on internal medicine patients with prophylactic anticoagulation. 16 However, and relevant to emergency medicine, the VTE risk and prevalence in outpatients with known or suspected COVID-19 is less studied. 17 The mixed results on the risk of VTE provides a challenge for the emergency physician when assessing pretest probability in patients with known or suspected COVID-19. If COVID-19 were an independent risk factor for VTE in outpatients, traditional approaches to risk stratification and diagnostic testing may need to be modified. The goal was to investigate if COVID-19 was associated with an increased risk of VTE in patients undergoing testing for VTE in a regional healthcare system in Sweden. In this retrospective observational study, we evaluated the risk and The exposure was COVID-19 infection, defined as a positive polymerase chain reaction (PCR) test up to 14 days before or 7 days after the diagnostic test for VTE. This timeframe was chosen a priori to account for the delay from symptom onset to deterioration 21 and delay to PCR test in the beginning of the pandemic. All patients with at least 1 diagnostic test for VTE during 2020 were matched with the regional severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) database of real-time PCR (RT-PCR) results. PCR was the diagnostic criteria for COVID-19 used in our system, and patients with a high probability for COVID-19 despite a negative PCR were tested repeatedly. PCR data were extracted from the healthcare system's central diagnostic laboratory, the only authorized SARS-CoV-2 laboratory during this period. Additional known risk factors for VTE were extracted from the EHR. In-hospital care on a ward or in the ICU was defined as a minimum The outcome was a diagnosis of VTE by CTPA or ultrasound. Written study reports were extracted from the picture archiving and com- Descriptive data were reported as percentage, mean with standard deviation (SD), or median with interquartile range (IQR This study was carried out in accordance with the Declaration of Helsinki. 27 There were 9973 diagnostic tests for VTE performed during the study period. After the exclusion of ineligible tests and a reduction for duplicate tests, a total of 8702 tests were included in the analysis ( Figure 1 ). This was a retrospective observational study, and the results are limited to the variables we were able to control for. We used the risk factors for PE and DVT defined by Wells et al, 28 whereas scintigraphy is rarely performed in our system. In addition, tests for cerebral venous sinus thrombosis were not included because of resource limitations. We based the classification of PE on the radiology report and not an independent read of the image data. Although this may have introduced a subjective interpretation, it reflects the actual practice in Sweden where non-radiologists rely on the report by the radiologists for the diagnosis of PE. An infection with SARS-CoV-2 virus confirmed on RT-PCR was not associated with an increased risk of VTE in patients undergoing a diagnostic test for VTE in a large, integrated healthcare system in Sweden. 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