Research
Published Papers
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Long COVID burden and risk factors in 10 UK longitudinal studies and electronic health records
This paper combines results from longitudinal cohort studies with electronic health data from OpenSAFELY, to describe how risk of long COVID varies amongst demographic and clinical factors.
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Safety of COVID-19 vaccination and acute neurological events
This paper investigates the potential association of COVID-19 vaccination with three acute neurological events: Guillain-Barré syndrome (GBS), transverse myelitis and Bell’s palsy.
Read more about Safety of COVID-19 vaccination and acute neurological events →
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Impact of First UK COVID-19 Lockdown on Hospital Admissions: Interrupted Time Series Study of 32 Million People
This study used OpenSAFELY (on behalf of NHS England), EAVEII (Scotland) and SAIL Databank (Wales) to investigate the weekly hospital admission rates for cancer, cardiovascular and respiratory conditions (excluding COVID-19) broken down by disease, sex, socioeconomic group and ethnicity group in a federated analysis across England, Scotland and Wales.
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Association between oral anticoagulants and COVID-19-related outcomes: a population-based cohort study
This paper investigates the association between OACs and COVID-19 outcomes in those with atrial fibrillation and a CHA2DS2-VASc score of 2.
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Potentially inappropriate prescribing of DOACs to people with mechanical heart valves: a federated analysis of 57.9 million patients’ primary care records in situ using OpenSAFELY
National guidance was issued during the COVID-19 pandemic to switch patients on warfarin to direct oral anticoagulants (DOACs) where appropriate as these require less frequent blood testing. DOACs are not recommended for patients with mechanical heart valves. We conducted a retrospective cohort study of DOAC prescribing in people with a record of a mechanical heart valve between September 2019 and May 2021, and describe the characteristics of this population.
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Comparison of methods for predicting COVID-19-related death in the general population using the OpenSAFELY platform
This paper evaluate different methods for predicting COVID-19-related death using the OpenSAFELY platform
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Overall and cause-specific hospitalisation and death after COVID-19 hospitalisation in England: A cohort study using linked primary care, secondary care, and death registration data in the OpenSAFELY platformr
This paper investigates whether risks of hospital admission and death, overall and by specific cause, are raised following discharge from a COVID-19 hospitalisation.
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Mortality among Care Home Residents in England during the first and second waves of the COVID-19 pandemic: an observational study of 4.3 million adults over the age of 65
This paper describe trends in the mortality risk among residents of care homes compared to private homes during the first and second waves of the COVID-19 pandemic in England.
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OpenSAFELY: impact of national guidance on switching anticoagulant therapy during COVID-19 pandemic
This paper describes which people were switched from warfarin to DOACs during the COVID-19 pandemic following an update in national guidance
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OpenSAFELY NHS Service Restoration Observatory 1: primary care clinical activity in England during the first wave of COVID-19
Working on behalf of NHS England, this study used the OpenSAFELY platform to describe the volume and variation of coded clinical activity in general practice between January 2019 and September 2020, taking respiratory disease and laboratory procedures as examples.
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Clinical coding of long COVID in English primary care: a federated analysis of 58 million patient records in situ using OpenSAFELY
Working on behalf of NHS England, this paper used the OpenSAFELY platform to measure the proportion of people with a recorded code for long COVID, overall and by demographic factors, electronic health record software system, and week.
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Association between warfarin and COVID-19-related outcomes compared with direct oral anticoagulants: population-based cohort study
This paper investigates the association between warfarin and COVID-19 outcomes compared with direct oral anticoagulants (DOACs)
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Trends and clinical characteristics of COVID-19 vaccine recipients: a federated analysis of 57.9 million patients’ primary care records in situ using OpenSAFELY
Working on behalf of NHS England this study analysed 57.9 million patient records in situ and in near-real-time within the infrastructure of the Electronic Health Record (EHR) software vendors EMIS and TPP using OpenSAFELY. The paper describes vaccine coverage and time trends across a range of demographic and fine-grained clinical subgroups in eight Joint Committee on Vaccination and Immunisation (JCVI) priority cohorts.
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Severity of Severe Acute Respiratory System Coronavirus 2 (SARS-CoV-2) Alpha Variant (B.1.1.7) in England
This paper aims to describe the severity of the alpha variant in terms of the pathway of disease from testing positive to hospital admission and death.
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Factors associated with deaths due to COVID-19 versus other causes: population-based cohort analysis of UK primary care data and linked national death registrations within the OpenSAFELY platform
Working on behalf of NHS England, this study investigates how specific factors are differentially associated with COVID-19 mortality as compared to mortality from other causes.
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Ethnic differences in SARS-CoV-2 infection and COVID-19-related hospitalisation, intensive care unit admission, and death in 17 million adults in England: an observational cohort study using the OpenSAFELY platform
Working on behalf of NHS England, this paper used the OpenSAFELY platform to quantify ethnic differences in SARS-CoV-2 infection and COVID-19 outcomes during the first and second waves of the COVID-19 pandemic in England.
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Identifying Care Home Residents in Electronic Health Records - An OpenSAFELY Short Data Report
This short data report describes the partial overlap between three methods for identifying care home residents in EHR, and provides detailed instructions for how to implement these in OpenSAFELY-TPP to support research into the impact of the COVID-19 pandemic on care home residents.
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Case fatality risk of the SARS-CoV-2 variant of concern B.1.1.7 in England, 16 November to 5 February
Working on behalf of NHS England, this paper uses the OpenSAFELY platform to estimate the risk of death following confirmation of SARS-CoV-2 infection in England, comparing infection with VOC to non-VOC, after accounting for demographic factors and comorbidities
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OpenSAFELY: Risks of COVID-19 hospital admission and death for people with learning disabilities - a cohort study
Working on behalf of NHS England, this paper used the OpenSAFELY platform to assess the association between learning disability and risk of hospitalisation and mortality from COVID-19 in England among adults and children.
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Association between living with children and outcomes from covid-19: OpenSAFELY cohort study of 12 million adults in England
Working on behalf of NHS England, this paper used the OpenSAFELY platform to investigate whether risk of infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and outcomes of coronavirus disease 2019 (covid-19) differed between adults living with and without children during the first two waves of the UK pandemic.
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HIV Infection and COVID-19 death: population-based cohort analysis of UK primary care data and linked national death registrations within the OpenSAFELY platform
Working on behalf of NHS England, this paper used the OpenSAFELY platform to investigate the association between HIV infection and COVID-19 mortality.
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Use of non-steroidal anti-inflammatory drugs and risk of death from COVID-19: an OpenSAFELY cohort analysis based on two cohorts
Working on behalf of NHS England, this paper used the OpenSAFELY platform to assess the association between routinely prescribed non-steroidal anti-inflammatory drugs (NSAIDs) and deaths from COVID-19.
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Effect of pre-exposure use of hydroxychloroquine on COVID-19 mortality: a population-based cohort study in patients with rheumatoid arthritis or systemic lupus erythematosus using the OpenSAFELY platform
Working on behalf of NHS England, this paper used the OpenSAFELY platform to investigate the effectiveness of hydroxychloroquine for prevention, as opposed to treatment, of COVID-19 mortality. We found no evidence of benefit or harm after adjusting for important differences between people with the same health conditions prescribed hydroxychloroquine or not.
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Risk of COVID-19-related death among patients with chronic obstructive pulmonary disease or asthma prescribed inhaled corticosteroids: an observational cohort study using the OpenSAFELY platform
Working on behalf of NHS England, this paper used the OpenSAFELY platform to investigate the association between ICS and COVID-19-related death among people with COPD or asthma using linked electronic health records (EHRs) in England, UK.
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OpenSAFELY: Factors associated with COVID-19 death in 17 million patients
Working on behalf of NHS England, this paper used the OpenSAFELY platform to quantify a range of clinical risk factors for COVID-19-related death in the largest cohort study conducted by any country to date.
Read more about OpenSAFELY: Factors associated with COVID-19 death in 17 million patients →
Pre-Prints
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Effectiveness of BNT162b2 booster doses in England: an observational study in OpenSAFELY-TPP
We estimate the effectiveness of boosting with BNT162b2 compared with no boosting in eligible adults who had received two primary course vaccine doses in England.
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OpenSAFELY: Representativeness of Electronic Health Record platform OpenSAFELY-TPP data compared to the population of England
This paper investigates the representativeness of OpenSAFELY-TPP data by comparing it to national population estimates.
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Comparative effectiveness of sotrovimab and molnupiravir for prevention of severe COVID-19 outcomes in non-hospitalised patients: an observational cohort study using the OpenSAFELY platform
This paper aims to compare the effectiveness of sotrovimab (a neutralising monoclonal antibody) vs. molnupiravir (an antiviral) in preventing severe COVID-19 outcomes in non-hospitalised high-risk COVID-19 adult patients
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Changes in English medication safety indicators throughout the COVID-19 pandemic: a federated analysis of 57 million patients’ primary care records in situ using OpenSAFELY
To describe the impact of the COVID-19 pandemic on safe prescribing, using the PINCER prescribing indicators; to implement complex prescribing indicators at national scale using GP data. This study uses a population based cohort study, with the approval of NHS England using the OpenSAFELY platform, covering Electronic health record data from 56.8 million NHS patients’ general practice records
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Association between household composition and severe COVID-19 outcomes in older people by ethnicity: an observational cohort study using the OpenSAFELY platform
This paper aims to quantify the association between household composition and risk of severe COVID-19 by ethnicity for older individuals
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Waning effectiveness of BNT162b2 and ChAdOx1 COVID-19 vaccines over six months since second dose: a cohort study using linked electronic health records
This paper investigates the rate at which COVID-19 vaccine effectiveness wanes over time
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Trends, regional variation and clinical characteristics of recipients of antivirals and neutralising monoclonal antibodies for non-hospitalised COVID-19: a descriptive cohort study of 23.4 million people in OpenSAFELY
This paper aims to develop a framework for detailed near real-time monitoring of treatment deployment, to ascertain eligibility status for patients and to describe trends and variation in coverage of treatment between geographic, clinical and demographic groups.
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Describing the population experiencing COVID-19 vaccine breakthrough following second vaccination in England: A cohort study from OpenSAFELY
This paper describes the characters of individuals who have experienced COVID-19 vaccine breakthrough after their second vaccination.
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Impact of First UK COVID-19 Lockdown on Hospital Admissions: Interrupted Time Series Study of 32 Million People
This study used OpenSAFELY (on behalf of NHS England), EAVEII (Scotland) and SAIL Databank (Wales) to investigate the weekly hospital admission rates for cancer, cardiovascular and respiratory conditions (excluding COVID-19) broken down by disease, sex, socioeconomic group and ethnicity group in a federated analysis across England, Scotland and Wales.
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Comparative effectiveness of ChAdOx1 versus BNT162b2 COVID-19 vaccines in Health and Social Care workers in England: a cohort study using OpenSAFELY
A compararison of the effectiveness of the BNT162b2 mRNA (Pfizer-BioNTech) and the ChAdOx1 (Oxford-AstraZeneca) COVID-19 vaccines against infection and COVID-19 disease in health and social care workers.
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Potentially inappropriate prescribing of DOACs to people with mechanical heart valves: a federated analysis of 57.9 million patients’ primary care records in situ using OpenSAFELY
National guidance was issued during the COVID-19 pandemic to switch patients on warfarin to direct oral anticoagulants (DOACs) where appropriate as these require less frequent blood testing. DOACs are not recommended for patients with mechanical heart valves. We conducted a retrospective cohort study of DOAC prescribing in people with a record of a mechanical heart valve between September 2019 and May 2021, and describe the characteristics of this population.
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HIV infection and COVID-19 death: population-based cohort analysis of UK primary care data and linked national death registrations within the OpenSAFELY platform
This paper uses the OpenSAFELY platform to investigate whether HIV infection is associated with risk of COVID-19 death
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Recording of “COVID-19 vaccine declined” among vaccination priority groups: a cohort study on 57.9 million NHS patients’ primary care records in situ using OpenSAFELY
A description of the patterns of usage of codes for COVID-19 vaccines being declined.
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Overall and cause-specific hospitalisation and death after COVID-19 hospitalisation in England: cohort study in OpenSAFELY using linked primary care, secondary care and death registration data
This paper aims to investigate whether risks of hospital admission and death, overall and by specific cause, are raised following discharge from a COVID-19 hospitalisation.
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Association between oral anticoagulants and COVID-19 related outcomes: two cohort studies
Working on behalf of NHS England, this study used the OpenSAFELY platform to investigate the role of routinely prescribed oral anticoagulants (OACs) in COVID-19 outcomes, comparing current OAC use versus non-use in Study 1; and warfarin versus direct oral anticoagulants (DOACs) in Study 2.
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Rates of serious clinical outcomes in survivors of hospitalisation with COVID-19: a descriptive cohort study within the OpenSAFELY platform
Patients with COVID-19 are thought to be at higher risk of cardiometabolic and pulmonary complications, but quantification of that risk is limited. Working on behalf of NHS England, this study aimed to describe the overall burden of these complications in survivors of severe COVID-19 using OpenSAFELY.
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Predicting COVID-19 related death using the OpenSAFELY platform
Working on behalf of NHS England, this study used the OpenSAFELY platform to compare approaches for obtaining relative and absolute estimates of risk of 28-day COVID-19 mortality for adults in the general population of England in the context of changing levels of circulating infection.
Read more about Predicting COVID-19 related death using the OpenSAFELY platform →
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Changes in the rate of cardiometabolic and pulmonary events during the COVID-19 pandemic
Working on behalf of NHS England, this study used the OpenSAFELY platform to describe the overall rate of various key clinical events over time, and their relationship with COVID-19.
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Short report: Ethnicity and COVID-19 death in the early part of the COVID-19 second wave in England: an analysis of OpenSAFELY data from 1st September to 9th November 2020
This short data report investigates whether there were ethic inequalities in COVID-19 death in the second wave in England
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Trends, regional variation, and clinical characteristics of COVID-19 vaccine recipients: a retrospective cohort study in 23.4 million patients using OpenSAFELY
Working on behalf of NHS England, this study used the OpenSAFELY platform to develop a framework for detailed near-real-time monitoring of COVID-19 vaccine roll-out; to describe trends and variation in coverage by geographic area, and between key clinical and demographic patient groups.
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Factors associated with deaths due to COVID-19 versus other causes: population-based cohort analysis of UK primary care data and linked national death registrations within the OpenSAFELY platform
This paper investigates the factors associated with deaths due to COVID-19 versus other causes
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OpenSAFELY: impact of national guidance on switching from warfarin to direct oral anticoagulants (DOACs) in early phase of COVID-19 pandemic in England
Working on behalf of NHS England, this study investigates which people were switched from warfarin to DOACs following national guidance during the first wave of the COVID-19 pandemic; seeks to identify potentially unsafe co-prescribing of anticoagulants; and assesses whether abnormal clotting results have become more frequent during the pandemic.
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Association between living with children and outcomes from COVID-19: an OpenSAFELY cohort study of 12 million adults in England
Working on behalf of NHS England, this study investigates whether risk of infection with SARs-CoV-2 and severe outcomes differed between adults living with and without children.
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Study protocol: Comparison of different risk prediction modelling approaches for COVID-19 related death using the OpenSAFELY platform
This protocol reports details of a planned study to explore the extent to which incorporating time-varying measures of infection burden over time improves the quality of risk prediction models for COVID-19 death in a large population of adult patients in England.
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Ethnic differences in COVID-19 infection, hospitalisation, and mortality: an OpenSAFELY analysis of 17 million adults in England
Working on behalf of NHS England, the aim of this study was to identify ethnic differences in the risk of COVID-19 infection, hospitalisation and mortality using a large general population cohort in England.
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Inhaled corticosteroid use and risk COVID-19 related death among 966,461 patients with COPD or asthma: an OpenSAFELY analysis
Working on behalf of NHS England, this paper used the OpenSAFELY platform to investigate the association between ICS and COVID-19-related death among people with COPD or asthma using linked electronic health records (EHRs) in England, UK.
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OpenSAFELY: factors associated with COVID-19-related hospital death in the linked electronic health records of 17 million adult NHS patients
Working on behalf of NHS England, this paper used the OpenSAFELY platform to quantify a range of clinical risk factors for COVID-19-related death in the largest cohort study conducted by any country to date.
Supplemental Research
Post-publications supplement to Williamson, E.J., Walker, A.J., Bhaskaran, K. et al. OpenSAFELY: factors associated with COVID-19 death in 17 million patients. Nature (2020). https://doi.org/10.1038/s41586-020-2521-4
August 2020. In the above paper, working on behalf of NHS England, we estimated associations between a wide range of individual-level factors including demographics and comorbidities, and risk of COVID-19 death, but we did not explore interactions between variables. It is plausible that associations may depend on age, and evaluating this would inform more accurate risk prediction. The purpose of this supplement is therefore to present associations between individual-level factors and COVID-19 death,stratified by age group.
Download the supplement here.