Central pulmonary embolism in patients with Covid-19.

BACKGROUND: The purpose was to evaluate central pulmonary embolism (PE) in patients with Covid-19. The association with severe radiological pulmonary changes, prophylactic anticoagulation and ICU care was assessed. METHODS: From 1 March until 31 May 2020, all in-hospital patients with a positive PCR for SARS-CoV-2-RNA and PE diagnosed with computed tomography pulmonary angiography were identified through diagnostic codes in medical charts. PE was characterised as central/peripheral and unilateral/bilateral. Covid-19 related lung changes were evaluated scoring the proportion of affected lung (max-score score 25) for all five lobes in both lungs. ICU and non-ICU patients were included and anticoagulant regimens were assessed. RESULTS: Of 1162 patients with Covid-19, 41 were diagnosed with PE (cumulative incidence 3.5%), and of these 63.4% (=overall 2.2%) had central PE. PE on admission was present in 46.3%. No differences were seen in the distribution of central vs. peripheral PE in relation to prophylactic anticoagulation (p=.317). Of ICU patients 82.4% were diagnosed with central PE compared to 50.0% among non-ICU patients (p=.05). No association was observed between the presence of central PE and the extent of radiological Covid-19 changes (p=.451). Mild (0-12 p) and severe (13-25 p) pulmonary changes were seen in 63.4% and 36.6% of patients respectively. CONCLUSIONS: Overall, and especially in ICU-patients, a high proportion of central PE was seen and many were diagnosed at admission. No association between central PE and prophylactic anticoagulation, or the extent of pulmonary Covid-19 changes was observed.

Analysis of Scientific Publications During the Early Phase of the COVID-19 Pandemic: Topic Modeling Study.

BACKGROUND: The COVID-19 pandemic has spread at an alarming speed, and effective treatment for the disease is still lacking. The body of evidence on COVID-19 has been increasing at an impressive pace, creating the need for a method to rapidly assess the current knowledge and identify key information. Gold standard methods such as systematic reviews and meta-analyses are regarded unsuitable because they have a narrow scope and are very time consuming. OBJECTIVE: This study aimed to explore the published scientific literature on COVID-19 and map the research evolution during the early phase of the COVID-19 pandemic. METHODS: We performed a PubMed search to analyze the titles, keywords, and abstracts of published papers on COVID-19. We used latent Dirichlet allocation modeling to extract topics and conducted a trend analysis to understand the temporal changes in research for each topic, journal impact factor (JIF), and geographic origin. RESULTS: Based on our search, we identified 16,670 relevant articles dated between February 14, 2020, and June 1, 2020. Of these, 6 articles were reports from peer-reviewed randomized trials on patients with COVID-19. We identified 14 main research topics, of which the most common topics were health care responses (2812/16,670, 16.86%) and clinical manifestations (1828/16,670, 10.91%). We found an increasing trend for research on clinical manifestations and protective measures and a decreasing trend for research on disease transmission, epidemiology, health care response, and radiology. Publications on protective measures, immunology, and clinical manifestations were associated with the highest JIF. The overall median JIF was 3.7 (IQR 2.6-5.9), and we found that the JIF for these publications declined over time. The top countries producing research were the United States, China, Italy, and the United Kingdom. CONCLUSIONS: In less than 6 months since the novel coronavirus was first detected, a remarkably high number of research articles on COVID-19 have been published. Here, we discuss and present the temporal changes in the available COVID-19 research during the early phase of the pandemic. Our findings may aid researchers and policy makers to form a structured view of the current COVID-19 evidence base and provide further research directions.