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The contribution of primary care and linked data to diabetes pharmacoepidemiology
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Strongman, Helen (2019) The contribution of primary care and linked data to diabetes pharmacoepidemiology. PhD thesis, University of Warwick.
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Official URL: http://webcat.warwick.ac.uk/record=b3876635
Abstract
Pharmacoepidemiology is the study of the use, effectiveness and safety of drugs in large populations. Studies commonly use data that are routinely collected in clinical care including electronic health records (EHR) from general practice linked to data collected in hospitals and other settings[1]. The strengths and challenges of using these data have often been demonstrated in studies of diabetes[2,3], a prevalent chronic health condition characterised by hyperglycaemia leading over time to microvascular and macrovascular disease[4].
The Clinical Practice Research Datalink (CPRD) is one of the main research data services worldwide providing de-identified primary care data linked to other health data sources for health research[5]. The publications that form this thesis were completed during my role in the Observational Research team at CPRD from 2011 to 2017. My aim was to improve the technical and information governance aspects of linking primary care data to other health datasets in the UK, inform development of new linked data sources, and demonstrate the value and best practice use of primary care and linked data through applied diabetes pharmacoepidemiology studies.
Paper 1[6] describes the methods used by National Health Service (NHS) Digital to link CPRD primary care data to other health data sources, the processing steps implemented by CPRD, and the implications of these methods for study design and reporting. I was the lead observational researcher guiding updates to these processes including changes to information governance processes and the addition of new datasets. Key messages resulting from this work are that CPRD and NHS Digital operate data linkages under a well governed and robust framework. These linkages enable a broader range of pharmacoepidemiology research, improved variable definitions, and obviate the need to link data for individual studies. Metadata are supplied to inform applied research design including selection of denominator populations and study periods. Further research is required to compare alternative linkage methodologies and explore potential biases introduced through the linkage process.
My applied research includes a study comparing secondary healthcare resource utilisation in patients prescribed alternative second line type 2 diabetes (T2DM) 14 regimens (Paper 2[7]) and a post-authorisation safety study (PASS) investigating bladder cancer and mortality outcomes following pioglitazone prescribing (Papers 3 to 5[8–10]). These examples demonstrate that primary care data can be used to identify patients with diabetes and a wide range of related exposures, outcomes and covariates for epidemiological research. Identification of conditions that are also treated in secondary care, secondary care resource utilisation and cause specific mortality can be improved with the use of linked data. Multiple decisions and assumptions are required to select data sources and study populations, define study variables and apply statistical analysis methodologies that account for missing data, avoid time-related biases, and minimise confounding. Methodological research is available to guide some of these decisions but should be considered in the context of the individual study and extended or updated if insufficient evidence exists. Applying the same methodology to pooled linked data sources from multiple countries can increase precision in investigating rare outcomes but does not eliminate heterogeneity due to systematic differences in diabetes patients and treatments between countries, and differences in data recording.
In summary, the work presented in this thesis shows primary care and linked health data to be important resources in diabetes pharmacoepidemiology, with standard linkages adding value to the data. My contribution to the establishment of linkage and information governance processes is described. My applied research addressed key clinical questions, and demonstrated the importance of developing and following best practice to optimise scientific quality, and increase confidence in these resources among the general public and policy makers.
Item Type: | Thesis (PhD) | ||||
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Subjects: | R Medicine > RA Public aspects of medicine R Medicine > RC Internal medicine R Medicine > RM Therapeutics. Pharmacology |
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Library of Congress Subject Headings (LCSH): | Pharmacoepidemiology, Diabetes -- Research, Primary care (Medicine) | ||||
Official Date: | November 2019 | ||||
Dates: |
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Institution: | University of Warwick | ||||
Theses Department: | Warwick Medical School | ||||
Thesis Type: | PhD | ||||
Publication Status: | Unpublished | ||||
Supervisor(s)/Advisor: | Mistry, Hema ; Bhaskaran, Krishnan | ||||
Format of File: | |||||
Extent: | 67 pages : illustration | ||||
Language: | eng |
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