TABLE 2

Characteristics of studies included in the review (n=12)

First author (year) [reference]CountryData sourcePopulationCOVID-19 confirmationData collection timeDesign
Aveyard (2021) [15]EnglandQResearch database version 44Adults (≥20 years) from 1205 general practices linked to all ICUs in EnglandRT-PCR test confirmed and suspected cases24 January to 30 April 2020Retrospective cohort study
Bloom (2021) [16]UKISARIC CCP-UK study (national, multicentre)Child (<16 years) and adult (≥16 years) inpatients from hospitals in England, Scotland and WalesRT-PCR test confirmed and suspected cases17 January to 17 August 2020Prospective cohort study
Choi (2021) [21]South KoreaHIRA COVID-19 nationwide patient medical claims dataChild (<19 years) and adult (≥20 years) inpatients and outpatients from hospitals in South KoreaRT-PCR testsMarch 2019 to 15 May 2020Retrospective cohort study
Eger (2020) [20]The NetherlandsDutch Severe Asthma Registry RAPSODI (national, multicentre)
DNIPESN database (Dutch general population)
1) Adults (≥18 years) from 15 hospitals for the RAPSODI registry
2) Adults (≥18 years) from the general population
RT-PCR test confirmed and suspected cases17 March to 30 April 2020Prospective cohort study
Fong (2021) [17]EnglandEHR (single centre)Adult (≥18 years) inpatients from a large tertiary hospitalRT-PCR test1 March to 31 May 2020Retrospective cohort study
Robinson (2022) [22]USAMGB Enterprise Data Warehouse, MGB Research Patient Data Registry and the COVID-19 Datamart (multicentre)Adult (≥18 years) inpatients and outpatients from hospitals in the greater Boston areaRT-PCR test4 March to 2 July 2020Retrospective cohort study
Schultze (2020) [18]UKOpenSAFELY primary care EHR data linked with death data from the Office for National Statistics in EnglandAdults (≥18 years) in EnglandRT-PCR test confirmed and suspected cases1 March to 6 May 2020Prospective cohort study
Williamson (2020) [19]EnglandOpenSAFELY primary care EHR data linked with death data from the Office for National Statistics in EnglandAdults (≥18 years) in EnglandRT-PCR test confirmed and suspected cases1 February to 6 May 2020Prospective cohort study
Jung (2021)# [23]South KoreaKorea National Health Insurance Database COVID-19 medical claims dataAdult (≥20 years) inpatients and outpatients from hospitals in South KoreaRT-PCR test1 January 2020 to 4 June 2020Retrospective cohort study
Shi (2022) [24]ScotlandEAVE II (national, multicentre)Children aged 5–17 years in ScotlandRT-PCR test1 March 2020 to 27 July 2021Retrospective cohort study
Shi (2022) [25]ScotlandEAVE II (national, multicentre)Adults (≥18 years) in ScotlandRT-PCR test1 March 2020 to 27 July 2021Retrospective cohort study
Zein (2022) [26]Ohio and Florida, USACleveland Clinic's COVID-19 research registryAdults (≥18 years) in Ohio and Florida, USART-PCR test1 April 2020 to 31 March 2021Retrospective cohort study

COVID-19: coronavirus disease 2019; ICU: intensive care unit; RT-PCR: reverse transcriptase PCR; ISARIC: International Severe Acute Respiratory and Emerging Infection Consortium; CCP-UK: World Health Organization Clinical Characterisation Protocol UK; HIRA: Health Insurance Review and Assessment Service; RAPSODI: Registry of Adult Patients with Severe Asthma for Optimal Disease Management; DNIPESN: Dutch National Institute for Public Health and the Environment and the Statistics Netherlands Database; EHR: electronic healthcare records; MGB: Mass General Brigham; EAVE II: Early Pandemic Evaluation and Enhanced Surveillance of COVID-19. #: separate estimates of hospitalisation, ICU admission and ventilation were not available; : the number of COVID-19 related deaths was small (n<5) in children with asthma.