Can instrumental variable analysis overcome confounding by indication? Validation of physicians' prescribing preferences as instrumental variables.
Department Name: Social Medicine
We will provide novel empirical and simulated evidence about the validity of physicians' prescribing preferences as instrumental variables and guidance about their interpretation and use to patients, clinicians, regulators and researchers.
In recent studies we have found evidence that instrumental variable analysis of electronic medical records can produce results comparable to a meta-analysis of randomised controlled trials (RCTs) for a fraction of the cost [13]. This suggests that instrumental variable analyses of observational studies could provide a useful additional source of reliable evidence.
Instrumental variable analysis may therefore be an extremely useful tool for pharmacoepidemiologists to investigate the effects of medications using observational data. Our results to date suggest that it is possible to obtain evidence as precise as all published experimental studies combined using an observational dataset. The combined investment in all 44 randomised studies included in our meta-analysis is likely to be orders of magnitude greater than the cost of conducting the analysis reported in Thomas et al. (2013). Furthermore, resources like the CPRD are continually accruing new data, both due to existing General Practices adding further years of records and because additional General Practices are added. Therefore, over time more observational data are becoming available which will greatly increase the precision of observational estimates. Eventually, this will allow researchers to address even more refined hypotheses such as the effect of treatments within pre-specified sub-groups of the population.
The results of this project will be written up as two papers. The first will present the results of the empirical negative control studies and the second will describe the simulation study. We anticipate both papers will merit publication in high impact medical or statistical journals, such as Statistics in Medicine and Epidemiology. We will present the results of these studies at two international conferences (specifically the International Society for Pharmacoepidemiology in Dublin 2016 and the Society for Epidemiologic Research in Miami in 2016). We have requested resources for these conference presentations and open access publication fees.
Aug 15 - Feb 17
MR/N01006X/1
Neil Davies
Health Category:
Generic Health Relevance (100%)
1.4 Methodologies and measurements (100%)
Neil Davies (Principal Investigator)
Frank Windmeijer (Co-Investigator) http://orcid.org/0000-0002-4232-2783
Richard Michael Martin (Co-Investigator)
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Davies N (2016) Effects of varenicline on adverse outcomes: an observational cohort study using electronic medical records in The Lancet
Davies Neil M. (2016) Effects of varenicline on adverse outcomes: an observational cohort study using electronic medical records in LANCET
Davies NM (2015) Cardiovascular and neuropsychiatric risks of varenicline: too good to be true? in The Lancet. Respiratory medicine
Davies NM (2017) The Food and Drug Administration and varenicline: should risk communication be improved? in Addiction (Abingdon, England)
Davies NM (2015) What are the effects of varenicline compared with nicotine replacement therapy on long-term smoking cessation and clinically important outcomes? Protocol for a prospective cohort study. in BMJ open
Davies NM (2018) The effects of prescribing varenicline on two-year health outcomes: an observational cohort study using electronic medical records. in Addiction (Abingdon, England)
Davies NM (2020) Varenicline versus nicotine replacement therapy for long-term smoking cessation: an observational study using the Clinical Practice Research Datalink. in Health technology assessment (Winchester, England)
Davies NM (2017) How to compare instrumental variable and conventional regression analyses using negative controls and bias plots. in International journal of epidemiology
Davies NM (2016) What is the effect of varenicline on long-term smoking abstinence in primary care patients?
Itani T (2019) Long-term effectiveness and safety of varenicline and nicotine replacement therapy in people with neurodevelopmental disorders: A prospective cohort study. in Scientific reports
Description CRUK Fellowship
Organisation Cancer Research UK
Description Efficient Study Designs call
Funding ID 15/80/19
Organisation National Institute for Health Research
Department Health Technology Assessment Programme (HTA)
Description Elizabeth Blackwell Institute Public Advisory Group
Results and Impact Presented our plans for the research to the EBI PAG. They gave feedback and suggested potential avenues for dissemination.
Description Presentation to UKCTAS Smokers' panel
Primary Audience Patients, carers and/or patient groups
Results and Impact We presented the results of our study to the UK CTAS Smokers' panel. The panel members gave feedback about our research and how we can disseminate our results to relevant groups.
Description Presented plans for research at Nottingham UKCTAS smokers' panel
Results and Impact We presented our plans for the research project to the UKCTAS smokers panel. The participants gave us feedback about the specific research questions they were interested in.