Alex Walker
Director of Research
Alex is an epidemiologist at the Bennett Institute. He has a particular interest in database linkage, time course analysis, risk stratification, prognosis modelling and novel computational methods in epidemiology. Before coming to Oxford he was a Senior Research Fellow at The University of Nottingham, where he worked on a variety of projects relating to several disease areas, including; hepatitis C, cancer and venous thromboembolism. His work to date has mostly focused on using routinely collected data - data sources such as the CPRD, HES and ONS data - to answer pragmatic and clinically relevant questions. He completed his PhD in the Division of Epidemiology and Public Health at Nottingham, which involved pharmacoepidemiology, commonly prescribed drugs and cancer. Before that he completed a MSc in Oncology and a BSc in Biochemistry and Genetics.
Papers by Alex Walker
- Impact of COVID-19 on recorded blood pressure screening and hypertension management in England
- Therapeutics Dataset from COVID-19 Medicine Delivery Units in England
- Consistency, completeness and external validity of ethnicity recording in NHS primary care records: a cohort study in 25 million patients’ records at source using OpenSAFELY
- Changes in sick notes associated with COVID-19 from 2020 to 2022: a cohort study in 24 million primary care patients in OpenSAFELY-TPP
- Effectiveness of mRNA COVID-19 Vaccines as First Booster Doses in England
- Changes in opioid prescribing during the COVID-19 pandemic in England
- Data-Driven Identification of Potentially Successful Intervention Implementations Using 5 Years of Opioid Prescribing Data
- OpenSAFELY: Effectiveness of COVID-19 vaccination in children and adolescents
- Clinical coding of long COVID in primary care 2020–2023 in a cohort of 19 million adults
- The impact of the COVID-19 pandemic on Antidepressant Prescribing with a focus on people with learning disability and autism
- Impact of long COVID on health-related quality-of-life: an OpenSAFELY population cohort study using patient-reported outcome measures (OpenPROMPT)
- The impact of COVID-19 on azathioprine, leflunomide and methotrexate monitoring, and factors associated with change in monitoring rate
- The impact of COVID-19 on medication reviews in English primary care
- Comparative safety and effectiveness of Pfizer BA.4-5 versus Sanofi during the spring 2023 COVID-19 booster vaccination programme in England
- Impact of vaccination on the association of COVID-19 with cardiovascular diseases
- During the COVID-19 pandemic 20 000 prostate cancer diagnoses were missed in England
- Measuring BMI in 22 million patients in England
- OpenSAFELY: a platform for analysing electronic health records designed for reproducible research
- Trends in inequalities in avoidable hospitalisations across the COVID-19 pandemic
- Educational interventions delivered to prescribing advisers to influence primary care prescribing: a very low-cost pragmatic randomised trial using routine data from OpenPrescribing.net
- Impact of COVID-19 on mental illness in vaccinated and unvaccinated people
- Impact of the COVID-19 pandemic on antipsychotic prescribing in individuals with autism, dementia, learning disability, serious mental illness or living in a care home
- Effect of the 2022 COVID-19 booster vaccination campaign in 50 year olds in England
- Healthcare in England was affected by the COVID-19 pandemic across the pancreatic cancer pathway
- Eleven key measures for monitoring general practice clinical activity during COVID-19
- Patient characteristics associated with clinically coded long COVID: an OpenSAFELY study using electronic health records
- A National Audit of Pancreatic Enzyme Prescribing in Pancreatic Cancer from 2015 to 2023 in England
- Changes in medication safety indicators in England throughout the covid-19 pandemic using OpenSAFELY
- Effectiveness of Sotrovimab and Molnupiravir in community settings in England across the Omicron BA.1 and BA.2 sublineages
- Challenges in Estimating the Effectiveness of COVID-19 Vaccination Using Observational Data
- Data-Driven Identification of Unusual Prescribing Behavior: Analysis and Use of an Interactive Data Tool Using 6 Months of Primary Care Data From 6500 Practices in England
- Comparative effectiveness of BNT162b2 versus mRNA-1273 covid-19 vaccine boosting in England
- First dose COVID-19 vaccine coverage amongst adolescents and children in England
- Trends, variation, and clinical characteristics of recipients of antiviral drugs and neutralising monoclonal antibodies for covid-19 in community settings
- OpenSAFELY NHS Service Restoration Observatory 2
- Factors associated with COVID-19 vaccine uptake in people with kidney disease
- Identifying Patterns of Clinical Interest in Clinicians' Treatment Preferences: Hypothesis-free Data Science Approach to Prioritizing Prescribing Outliers for Clinical Review
- Comparative effectiveness of sotrovimab and molnupiravir for prevention of severe covid-19 outcomes in patients in the community
- Recording of ‘COVID-19 vaccine declined’
- Waning effectiveness of BNT162b2 and ChAdOx1 covid-19 vaccines over six months since second dose
- Comparative effectiveness of ChAdOx1 versus BNT162b2 COVID-19 vaccines in Health and Social Care workers in England
- Representativeness of electronic health record platform OpenSAFELY-TPP data compared to the population of England
- Describing the population experiencing COVID-19 vaccine breakthrough following second vaccination in England
- Association between oral anticoagulants and COVID-19-related outcomes
- Long COVID burden and risk factors in 10 UK longitudinal studies and electronic health records
- Safety of COVID-19 vaccination and acute neurological events
- Impact of First UK COVID-19 Lockdown on Hospital Admissions
- Accident and emergency (AE) attendance in England following infection with SARS-CoV-2 Omicron or Delta
- Rates of serious clinical outcomes in survivors of hospitalisation with COVID-19 in England
- Comparison of methods for predicting COVID-19-related death in the general population using the OpenSAFELY platform
- Potentially inappropriate prescribing of DOACs to people with mechanical heart valves
- Overall and cause-specific hospitalisation and death after COVID-19 hospitalisation
- Mortality among Care Home Residents in England during the first and second waves of the COVID-19 pandemic
- OpenSAFELY NHS Service Restoration Observatory 1: primary care clinical activity in England during the first wave of COVID-19
- Trends and clinical characteristics of COVID-19 vaccine recipients
- Impact of national guidance on switching anticoagulant therapy during COVID-19 pandemic
- Clinical coding of long COVID in English primary care
- Association between warfarin and COVID-19-related outcomes compared with direct oral anticoagulants
- Severity of Severe Acute Respiratory System Coronavirus 2 (SARS-CoV-2) Alpha Variant (B.1.1.7) in England
- Risks of covid-19 hospital admission and death for people with learning disability
- Factors associated with deaths due to COVID-19 versus other causes
- Ethnic differences in SARS-CoV-2 infection and COVID-19-related hospitalisation, intensive care unit admission, and death in 17 million adults in England
- Identifying Care Home Residents in Electronic Health Records
- Association between living with children and outcomes from covid-19
- Case fatality risk of the SARS-CoV-2 variant of concern B.1.1.7
- Changes in the rate of cardiometabolic and pulmonary events during the COVID-19 pandemic
- Short report: Ethnicity and COVID-19 death in the early part of the COVID-19 second wave in England
- Use of non-steroidal anti-inflammatory drugs and risk of death from COVID-19
- HIV infection and COVID-19 death
- Effect of pre-exposure use of hydroxychloroquine on COVID-19 mortality
- Impact of Electronic Health Record Interface Design on Unsafe Prescribing of Ciclosporin, Tacrolimus, and Diltiazem: Cohort Study in English National Health Service Primary Care
- Comparison of different risk prediction modelling approaches for COVID-19 related death using the OpenSAFELY platform
- Risk of COVID-19-related death among patients with chronic obstructive pulmonary disease or asthma prescribed inhaled corticosteroids
- Suboptimal prescribing behaviour associated with clinical software design features: a retrospective cohort study in English NHS primary care
- Prescription of suboptimal statin treatment regimens: a retrospective cohort study of trends and variation in English primary care
- Factors associated with COVID-19-related death using OpenSAFELY
- Trends and variation in unsafe prescribing of methotrexate: a cohort study in English NHS primary care.
- Variation in responsiveness to warranted behaviour change among NHS clinicians: novel implementation of change detection methods in longitudinal prescribing data
- Impact of Chief Medical Officer activity on prescribing of antibiotics in England: an interrupted time series analysis
- Is Use of Homeopathy Associated With Poor Prescribing in English Primary Care? A Cross-Sectional Study
- Optimising laboratory monitoring of chronic conditions in primary care
- Do doctors in dispensing practices with a financial conflict of interest prescribe more expensive drugs? A cross-sectional analysis of English primary care prescribing data.
- Measuring the Impact of an Open Web-Based Prescribing Data Analysis Service on Clinical Practice: Cohort Study on NHS England Data
- Why did some practices not implement new antibiotic prescribing guidelines on urinary tract infection? A cohort study and survey in NHS England primary care
- Opioid prescribing trends and geographical variation in England, 1998–2018: a retrospective database study
- Six months on – NHS England needs to focus on dissemination, implementation and audit of its Low-Priority Initiative
- Time trends and geographical variation in prescribing of antibiotics in England 1998–2017
- Detecting Change in Comparison to Peers in NHS Prescribing Data: a Novel Application of Cumulative Sum Methodology
- The clinician impact and financial cost to the NHS of litigation over pregabalin: a cohort study in English primary care
- Trends and variation in prescribing of low-priority treatments identified by NHS England: a cross-sectional study and interactive data tool in English primary care
- Time trends and geographical variation in prescribing of drugs for diabetes in England from 1998 to 2017
- Impact of NICE guidance on tamoxifen prescribing in England 2011–2017: an interrupted time series analysis
- Trends, geographical variation and factors associated with prescribing of gluten-free foods in English primary care: a cross-sectional study
- New mechanism to identify cost savings in English NHS prescribing: minimising 'price per unit', a cross-sectional study
Blog posts by Alex Walker
- We're hiring!
- Bennett Conference session 4: OpenSAFELY research highlights, external perspectives & Peter Bennett
- We're hiring! CLOSES SOON!
- OpenSAFELY Research Highlights
- Communicating variation in prescribing - Why We Use Deciles
- Smoothing seasonality - your feedback needed
- Trends and variation in gluten-free food prescribing