BMJ Confidential: For Review Only Temporal trends in the use of tests in UK primary care: a retrospective analysis of 250 million tests, 2000 – 2015. Journal: BMJ Manuscript ID BMJ.2018.044789 Article Type: Research BMJ Journal: BMJ Date Submitted by the Author: 26-Apr-2018 Complete List of Authors: O'Sullivan, Jack; University of Oxford, Centre for Evidence-based medicine, Nuffield Department of Primary Care Health Sciences Stevens, Sarah; University of Oxford, Primary Care Health Sciences Hobbs, FD Richard; University of Oxford, Nuffield Department of Primary Care Health Science Salisbury, Chris; University of Bristol, Centre for Academic Primary Care, School of Social and Community Medicine Little, Paul; University of Southampton, Medical School, Goldacre, Ben; University of Oxford, Primary Care Health Sciences Bankhead, Clare; University of Oxford, Nuffield Department of Primary Care Health Sciences Aronson, Jeffrey; University of Oxford, Primary Health Care Perera, Rafael; University of Oxford, Primary Health Care Heneghan, Carl; Oxford University, Primary Health Care Too much medicine, Primary Care, Imaging, Laboratory tests, Radiology, Keywords: Workload https://mc.manuscriptcentral.com/bmj Page 1 of 100 BMJ 1 2 3 Temporal trends in the use of tests in UK primary care: a retrospective analysis of 250 million 4 tests, 2000 – 2015. 5 Jack W. O’Sullivan,1,2 Sarah Stevens,2 FD Richard Hobbs,2 Chris Salisbury,3 Paul Little,4 Ben 6 1,2 1,2 1,2 1,2 1,2 7 Goldacre, Clare Bankhead, Jeffrey K. Aronson, Rafael Perera, and Carl Heneghan . 8 9 10 1CentreConfidential: for Evidence-Based Medicine, Nuffield For Department Review of Primary Care HealthOnly Sciences, 11 University of Oxford, OX2 6GG, UK 12 2 13 Nuffield Department of Primary Care Health Sciences, University of Oxford, OX2 6GG, UK 14 3Centre for Academic Primary Care, School of Social and Community Medicine, University of 15 16 Bristol, BS8 2PS, UK 17 4Primary Care and Population Sciences, University of Southampton, Southampton, SO17 1BJ, UK 18 19 20 21 Jack W. O’Sullivan, Clinical Researcher and DPhil Candidate, [email protected] 22 Sarah Stevens, Statistician, [email protected] 23 24 FD Richard Hobbs, Professor of Primary Care Health Sciences, [email protected] 25 26 Chris Salisbury, Professor of Primary Health Care, [email protected] 27 Paul Little, Professor of Primary Care Research, [email protected] 28 29 Ben Goldacre, Senior Clinical Research Fellow, [email protected] 30 31 Clare Bankhead, Associate Professor of Primary Care, [email protected] 32 Jeffrey K. Aronson, Clinical Pharmacologist, [email protected] 33 34 Rafael Perera, Professor of Medical Statistics, [email protected] 35 36 Carl Heneghan, Professor of Evidence-Based Medicine, [email protected] 37 38 39 Correspondence to: Dr Jack W O’Sullivan 40 41 Centre for Evidence-Based Medicine 42 43 Nuffield Department of Primary Care Health Sciences 44 Radcliffe Observatory Quarter, Oxford, OX2 6GG 45 46 [email protected] 47 48 01865 289300 49 50 51 Manuscript word count: 3,565 52 53 Number of references: 31 54 55 56 57 58 59 60 https://mc.manuscriptcentral.com/bmj BMJ Page 2 of 100 1 2 3 Temporal trends in the use of tests in UK primary care: a retrospective analysis of 250 4 million tests, 2000 – 2015. 5 6 Abstract 7 8 Objectives 9 To assess the temporal change in UK primary care test use and identify tests with the greatest 10 11 increaseConfidential: in use. For Review Only 12 Design 13 14 Retrospective cohort study 15 16 Setting 17 18 UK primary care 19 20 Participants 21 All patients registered to UK General Practices in the Clinical Practice Research Datalink, 22 2000/1 to 2015/16. 23 24 Main outcome measure 25 26 We used data from the Clinical Practice Research Datalink to retrospectively analyse 27 temporal trends in the use of tests from UK general practices from 2000/1 to 2015/16. We 28 calculated crude and age- and sex-standardised rates of total test use and of 44 specific tests. 29 30 Results 31 32 We analysed 262,974,099 tests over 71,436,331 person-years. Age- and sex-adjusted use 33 increased by 8.5% annually (95%CI 7.6 – 9.4%); from 14,869 tests per 10,000 person-years 34 in 2000/1 to 49,267 in 2015/16, a 231% increase. Patients in 2015/16 had on average 5 tests 35 per year, compared with 1.5 in 2000/1. Test use also increased significantly across all age 36 37 groups, in both sexes, all test types (laboratory, imaging, and miscellaneous), and 40 of the 44 38 tests that we studied specifically. 39 40 Conclusion 41 Our findings contribute to a better understanding of primary care activities and can inform 42 43 future resource allocation. The significant increase in test use, which has outstripped 44 population growth, may be both a cause and a consequence of increasing GP workload. The 45 increasing rate of test use in UK general practice is unlikely to be sustainable. Furthermore, 46 the increase in almost all tests we studied specifically and the increase in the number of tests 47 ordered per patient are concerning for overtesting. 48 49 Funding 50 51 National Institute for Health Research. 52 53 Abstract word count: 243 54 55 56 57 58 59 60 https://mc.manuscriptcentral.com/bmj Page 3 of 100 BMJ 1 2 3 Introduction 4 5 The NHS is experiencing an unprecedented rise in spending [1]. Since 2003, net expenditure 6 has increased by over £50bn, an approximate 80% rise [1]. These increasing costs threaten 7 the sustainability of the NHS. 8 9 Primary care accounts for 90% of all NHS care [2]. Few studies have explored primary care 10 activities,Confidential: despite their importance and callsFor for urgent Review research [2]. There Only are no official 11 statistics on one of the core services provided by UK General Practitioners (GPs) – the use of 12 tests. Prior research focused on only a few specific tests in a small population sample [3]. 13 14 Tests account for a substantial proportion of the NHS budget – around £2-3bn annually for 15 laboratory tests alone – and influence more than 70% of clinical decisions [4]. We have 16 therefore quantified the temporal changes in the use of tests in UK general practice and have 17 18 identified specific tests for which usage has changed the most. 19 Methods 20 21 Study population 22 23 We obtained electronic health record data from patients registered with general practices 24 contributing to the Clinical Practice Research Datalink (CPRD) during April 1st 2000 to 25 March 31st 2016. The CPRD, a large database of anonymised electronic health records from 26 UK primary care, contains patient-level data covering approximately 7% of the UK 27 28 population [5]. CPRD data have been validated extensively and are representative of the UK 29 population in terms of age, sex [5], and ethnic background [6]. We included patients of any 30 age if their records were acceptable for research purposes (a data quality indicator provided 31 by CPRD) and were registered at practices with continuous high-quality data reporting 32 (CPRD defined up-to-standard) [7] at any time during the study period. The protocol was 33 approved by the Independent Scientific Advisory Committee (ISAC) of the MHRA (ISAC 34 35 protocol number 17_06R; available from the authors on request). Ethics approval for 36 observational research using the CPRD with approval from ISAC was granted by a National 37 Research Ethics Service committee (Trent MultiResearch Ethics Committee, REC reference 38 number 05/MRE04/87). 39 40 Included tests 41 42 We studied all tests recorded in the CPRD primary care record during the study period. The 43 CPRD contains primary care data, while secondary care data is captured in a separate 44 database and was not included in this study. We also excluded physical examination findings, 45 vital signs, and body weights. 46 47 Tests were grouped into one of three groups: laboratory, imaging, or miscellaneous. The 48 miscellaneous group included tests such as spirometry, upper endoscopy, colonoscopy, 49 Papanicolaou smears, and electrocardiography (ECG). To avoid double counting, if the same 50 code was recorded multiple times for the same patient on the same day, it was counted as 51 52 only one test. Similarly, codes that referred to the same test, or separate components of a 53 single test (e.g. individual components of a full blood count), were grouped and counted as 54 one test. 55 56 57 58 59 60 https://mc.manuscriptcentral.com/bmj BMJ Page 4 of 100 1 2 3 We also examined 44 specific tests (28 laboratory, 11 imaging, and five miscellaneous tests), 4 chosen because they are commonly used tests, included in guidelines or in the Quality 5 Outcomes Framework (QOF) (supplementary file). 6 7 Statistical analysis 8 9 The total number of tests recorded in general practice was calculated for each year, stratified 10 by ageConfidential: and sex. We calculated total person-years For ofReview observation in each Onlyage and sex stratum 11 for each year. Patients alive and registered for the entire year contributed 1 person-year of 12 observation to the total. Patients who were born, died, registered, or deregistered during the 13 year were included, but their contribution to the person-year calculation was adjusted 14 15 proportionately (e.g. a patient who was registered and alive for only 6 months contributed 0.5 16 person-years).