COVID‐19 and its cardiovascular effects: a systematic review of prevalence studies

Background A small minority of people with coronavirus disease 2019 (COVID‐19) develop a severe illness, characterised by inflammation, microvascular damage and coagulopathy, potentially leading to myocardial injury, venous thromboembolism (VTE) and arterial occlusive events. People with risk factors for or pre‐existing cardiovascular disease may be at greater risk. Objectives To assess the prevalence of pre‐existing cardiovascular comorbidities associated with suspected or confirmed cases of COVID‐19 in a variety of settings, including the community, care homes and hospitals. We also assessed the nature and rate of subsequent cardiovascular complications and clinical events in people with suspected or confirmed COVID‐19. Search methods We conducted an electronic search from December 2019 to 24 July 2020 in the following databases: the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, covid‐19.cochrane.org, ClinicalTrials.gov and EU Clinical Trial Register. Selection criteria We included prospective and retrospective cohort studies, controlled before‐and‐after, case‐control and cross‐sectional studies, and randomised controlled trials (RCTs). We analysed controlled trials as cohorts, disregarding treatment allocation. We only included peer‐reviewed studies with 100 or more participants, and excluded articles not written in English or only published in pre‐print servers. Data collection and analysis Two review authors independently screened the search results and extracted data. Given substantial variation in study designs, reported outcomes and outcome metrics, we undertook a narrative synthesis of data, without conducting a meta‐analysis. We critically appraised all included studies using the Joanna Briggs Institute (JBI) checklist for prevalence studies and the JBI checklist for case series. Main results We included 220 studies. Most of the studies originated from China (47.7%) or the USA (20.9%); 9.5% were from Italy. A large proportion of the studies were retrospective (89.5%), but three (1.4%) were RCTs and 20 (9.1%) were prospective. Using JBI’s critical appraisal checklist tool for prevalence studies, 75 studies attained a full score of 9, 57 studies a score of 8, 31 studies a score of 7, 5 studies a score of 6, three studies a score of 5 and one a score of 3; using JBI’s checklist tool for case series, 30 studies received a full score of 10, six studies a score of 9, 11 studies a score of 8, and one study a score of 5 We fo