Temporal trends in use of tests in UK primary care, 2000-15: retrospective analysis of 250 million testsBMJ 2018; 363 doi: https://doi.org/10.1136/bmj.k4666 (Published 28 November 2018) Cite this as: BMJ 2018;363:k4666
- Jack W O’Sullivan, clinical researcher1 2 3 4,
- Sarah Stevens, statistician2,
- F D Richard Hobbs, professor of primary care health sciences2,
- Chris Salisbury, professor of primary health care5,
- Paul Little, professor of primary care research6,
- Ben Goldacre, senior clinical research fellow12,
- Clare Bankhead, associate professor of primary care12,
- Jeffrey K Aronson, clinical pharmacologist12,
- Rafael Perera, professor of medical statistics12,
- Carl Heneghan, professor of evidence-based medicine12
- 1Centre for Evidence-Based Medicine, Nuffield Department of Primary Care Health Sciences, University of Oxford, Oxford OX2 6GG, UK
- 2Nuffield Department of Primary Care Health Sciences, University of Oxford, Oxford, UK
- 3Center for Inherited Cardiovascular Disease, Stanford University, Stanford, CA, USA
- 4Meta-Research Innovation Center at Stanford (METRICS), Stanford University, Stanford, CA, USA
- 5Centre for Academic Primary Care, Department of Population Health Sciences, Bristol Medical School, University of Bristol, Bristol, UK
- 6Primary Care and Population Sciences, University of Southampton, Southampton, UK
- Correspondence to: J W O’Sullivan @drjackosullivan on Twitter) (or
- Accepted 29 October 2018
Objectives To assess the temporal change in test use in UK primary care and to identify tests with the greatest increase in use.
Design Retrospective cohort study.
Setting UK primary care.
Participants All patients registered to UK General Practices in the Clinical Practice Research Datalink, 2000/1 to 2015/16.
Main outcome measures Temporal trends in test use, and crude and age and sex standardised rates of total test use and of 44 specific tests.
Results 262 974 099 tests were analysed over 71 436 331 person years. Age and sex adjusted use increased by 8.5% annually (95% confidence interval 7.6% to 9.4%); from 14 869 tests per 10 000 person years in 2000/1 to 49 267 in 2015/16, a 3.3-fold increase. Patients in 2015/16 had on average five tests per year, compared with 1.5 in 2000/1. Test use also increased statistically significantly across all age groups, in both sexes, across all test types (laboratory, imaging, and miscellaneous), and 40 of the 44 tests that were studied specifically.
Conclusion Total test use has increased markedly over time, in both sexes, and across all age groups, test types (laboratory, imaging, and miscellaneous) and for 40 of 44 tests specifically studied. Of the patients who underwent at least one test annually, the proportion who had more than one test increased significantly over time.
Contributors: JOS, CH, RP, BG, and FDRH conceived the study. JOS, RP, CB, and SS designed the study, which was further refined by general practitioner experts CH, FDRH, PL, and CS. JOS drafted the protocol, which all authors contributed to and revised critically. JOS and SS were responsible for data management. JOS, SS, and RP did the statistical analyses. JOS drafted the manuscript, to which all authors contributed, revised critically, and approved. JOS is the guarantor. The corresponding author attests that all listed authors meet authorship criteria and that no others meeting the criteria have been omitted.
Funding: This study was funded by an independent grant from the National Institute for Health Research (NIHR) School of Primary Care Research (reference No 386) and the Primary Care Research Trust. JOS is a doctoral student supported by the Clarendon Fund. FDRH is a general practitioner and research lead with the Modality Partnership, and director of the NIHR School for Primary Care Research. FDRH acknowledges part funding support from the NIHR School for Primary Care Research, the NIHR Oxford BRC, and the NIHR CLAHRC Oxford. CS is a member of the NIHR Health Services and Delivery Research Board and acknowledges support from NIHR CLAHRC West and NHS Bristol Clinical Commissioning Group. CH has received expenses and fees for his media work including BBC Inside Health. He holds grant funding from the NIHR, the NIHR School of Primary Care Research, the Wellcome Trust, and World Health Organization. He has also received income from a series of toolkit books published by Blackwells. With some international partners, CEBM jointly runs the EvidenceLive Conference and the Overdiagnosis Conference, which are based on a non-profit model. CB is partially supported by the NIHR Biomedical Research Centre, Oxford. Independent expert peer reviewers provided feedback on the grant application underpinning this study but had no further role in study design, data collection, analysis, interpretation, or drafting of the manuscript.
Competing interests: All authors have completed the ICMJE uniform disclosure form at www.icmje.org/coi_disclosure.pdf and declare: no support from any organisation for the submitted work; no financial relationships with any organisations that might have an interest in the submitted work in the previous three years; no other relationships or activities that could appear to have influenced the submitted work.
Ethical approval: This study was approved by Trent MultiResearch Ethics Committee (reference No 05/MRE04/87). The protocol was approved by the independent scientific advisory committee of the MHRA (protocol No 17_06R; available from the authors on request).
Data sharing: The General Practices in the Clinical Practice Research Datalink (CPRD) is run by the UK Department of Health. All the data are available via an application to the CPRD. Data acquisition is associated with a fee.
Transparency: The manuscript’s guarantor (JOS) affirms that the manuscript is an honest, accurate, and transparent account of the study being reported; that no important aspects of the study have been omitted; and that any discrepancies from the study as planned (and, if relevant, registered) have been explained.
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