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University of Exeter Medical School

Dr Zhivko Zhelev

Dr Zhivko Zhelev

Senior Research Fellow

 zz237@exeter.ac.uk

 6093

 +44 (0) 1392 726093

 South Cloisters 3.09

 

South Cloisters, University of Exeter, St Luke's Campus, Heavitree Road, Exeter, EX1 2LU, UK


Overview

Although my background is in clinical psychology and systemic family therapy, I have in the past 12 years worked as a health services researcher. Most of my research relates to the evaluation and use of medical tests spanning both primary and secondary research and encompassing a wide range of quantitative and qualitative study designs. I have led on a number of systematic reviews of test accuracy evaluations on topics, such as artificial intelligence based screening for diabetic retinopathy, hearing screening in children, pre-hospital tests for patients suspected of having stroke and tests for cow’s milk protein allergy. Some of these were commissioned by and informed the policy decisions made by government bodies, such as the UK National Screening Committee.

I have also worked on various methodology projects related to the taxonomy and reporting of test accuracy studies, the methods of test evaluation used by international HTA agencies, and the evaluation of artificial intelligence based medical tests.

I am a member of the Exeter Test Group. Recently, I have also joined the NIHR HSDR Evidence Synthesis Centre where I contribute to various evidence synthesis projects.

Broad research specialisms:

  • Systematic reviews and evidence syntheses for policy making
  • Primary and secondary research related to the evaluation and use of medical tests
  • Health economic modelling, particularly for the evaluation of medical tests
  • Assessment of the effectiveness and cost-effectiveness of artificial intelligence based medical tests

Qualifications

Learning and Teaching in Higher Education (LTHE) programme (Unit 1 completed, currently enrolled on Units 2-6)

Advanced training in Decision Modelling for Health Economic Evaluation (University of York, 2022)

PhD, Disability Discourses in Modern Bulgarian Society (University of Plymouth, 2009)

Advanced Clinical Training in Systemic Family Therapy (University of London & New Bulgarian University, 2000)

MSc in Clinical Psychology (University of Sofia, 1994)

BSc in Psychology (University of Sofia, 1992)

Career

I completed the Masters in Clinical Psychology programme (University of Sofia, Bulgaria) in 1994. I worked as a clinical psychologist and lecturer in psychology at the New Bulgarian University and Burgas Free University until 2001. More specifically, I was a cofounder of the New Bulgarian University’s counselling service for students with substance abuse problems and the Bulgarian National Harm Reduction programme; I initiated various projects for families with disabled children, such as family counselling provided in conjunction with horseback riding therapy. I was also part of a team that initiated various collaboration research and leadership development projects with Roma communities in different parts of Bulgaria. I was involved in setting up and running the Social Work programme at the Burgas Free University and worked there as a lecturer until 2001. In 2000 I completed my Advanced Clinical Training in Systemic Family Therapy and contributed to the setting up of the Family Therapy programme at the New Bulgarian University. From 1997 to 2001 I acted as a Clinical Director of a private counselling centre in Sofia, Bulgaria.

I moved to the UK in 2001 and worked as а care assistant at residential homes for young people with learning disabilities. In 2004 I joined the Little House Contact Centre team in Exeter. My role there was to prepare assessments for family courts and provide support and safe environment for contact between children and non-resident parents, especially when there are allegations or risk of child abuse or domestic violence. Between 2009 and 2011 I worked as a Research and Development Officer at The Dartington Hall Trust, as part of their Research for Adults team. My role was to prepare evidence syntheses reports commissioned by adult social services teams from different local authorities.

I joined the University of Exeter Medical School in 2011. Initially, I worked as a qualitative researcher looking at the difficulties that clinicians and policy makers experience when interpreting the results from Cochrane diagnostic accuracy reviews. Later I was appointed as a research fellow in diagnostics within the NIHR Applied Research Collaboration South West Peninsula (PenCLAHRC) working mostly on systematic reviews of test accuracy studies. Since 2018 I’ve been working on a string of systematic review projects commissioned by Public Health England.  

Links

Research group links

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Research

Research interests

I have a particular interest in the following research areas:

  • philosophy and social theory of evidence-based healthcare
  • communication of research evidence, especially related to medical tests, to various audiences
  • teaching evidence-based practice
  • multidisciplinary research
  • the relationship between environment and health

Research projects

Current active projects:

  • Improving communication and information sharing between health services, social care services and social care providers: a realist review
  • A health economic model of an AI-based skin cancer detection device
  • Evaluation of AI-based technology for medical imaging analysis: A methodological review and guidance
  • Remote monitoring for long-term physical health conditions: An evidence and gap map
  • Accuracy of serial high-sensitivity troponin for the diagnosis of myocardial infarction: a systematic review
  • A review of the diagnostic stability of autism spectrum disorders, and of the accuracy of screening tools and effectiveness of early interventions in pre-school children under the age of 5 years
  • Health Technology Assessment of Diagnostic Tests: A state of the art review of methods guidance from international organisations

Recent projects:

  • Test accuracy of artificial intelligence-based grading of fundus images in diabetic retinopathy screening: A systematic review
  • Human papillomavirus (HPV) screening in vaccinated populations: A systematic review of mathematical models
  • A review of the scientific evidence and guidelines on the accuracy and validity of HbA1c Point of Care Testing (POCT), when used in a non-laboratory setting compared to venous blood testing
  • SAMueL: Using simulation and machine learning to maximise the benefit of intravenous thrombolysis in acute stroke in England and Wales
  • Amplitude-integrated electroencephalography compared with conventional video-electroencephalography for detection of neonatal seizures: A Cochrane review

Past projects:

  • Prehospital stroke scales as screening tools for early identification of stroke and transient ischemic attack
  • A programme of studies including assessment of diagnostic accuracy of school hearing screening tests and a cost-effectiveness model of school entry hearing screening programmes
  • A qualitative study into the difficulties experienced by healthcare decision makers when reading a Cochrane diagnostic test accuracy review
  • Diagnostic accuracy of single baseline measurement of Elecsys Troponin T high-sensitive assay for diagnosis of acute myocardial infarction in emergency department: systematic review and meta-analysis
  • Redesigning the diagnostic pathway for chest pain patients in emergency departments
  • Use of test accuracy study design labels in NICE's diagnostic guidance
  • Autoantibody status for the prediction of future insulin deficiency in patients with diabetes: a systematic review
  • UNTEST: A programme of studies investigating the incidence of inappropriately ordered thyroid function tests (TFTs) in primary care, the factors affecting the ordering of TFTs and the effectiveness of interventions designed to improve appropriate use of TFTs

Research grants

  • 2021 Public Health England
    Validation of Artificial Intelligence systems for medical imaging in screening programmes
  • 2020 Public Health England
    Automated grading to replace level 1 graders in the Diabetic Eye Screening Programme
  • 2020 Public Health England
    Diagnostic stability of autism spectrum disorders, and of the accuracy of screening tools and effectiveness of early interventions in pre-school children under the age of 5 years
  • 2020 NIHR Health Services and Delivery Research
    Using simulation and machine learning to maximise the benefit of intravenous thrombolysis in acute stroke in England and Wales (SAMueL)
  • 2019 Public Health England
    Review of the accuracy of HbA1c point-of-care testing
  • 2019 Public Health England
    Human papillomavirus screening in vaccinated populations
  • 2018 Fujita University
    Diagnostic accuracy of serial high-sensitivity cardiac troponin for diagnosis of myocardial infarction

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Publications

Journal articles

Ukoumunne OC, Hyde C, Ozolins M, Zhelev Z, Errington S, Taylor RS, Benton C, Moody J, Cocking L, Watson J, et al (In Press). A directly comparative two-gate case-control diagnostic accuracy study of the pure tone screen and HearCheck Screener tests for identifying hearing impairment in school children. BMJ Open
Zhelev Z, Ohtake H, Iwata M, Terasawa T, Rogers M, Peters J, Hyde C (In Press). Diagnostic accuracy of contemporary and high-sensitivity cardiac troponin assays used in serial testing, versus single-sample testing as a comparator, to triage patients suspected of acute non- ST-segment elevation myocardial infarction: a systematic review protocol. BMJ Open Abstract.
Hardwick RJL, Heaton J, Griffiths G, Vaidya B, Child S, Fleming S, Hamilton WT, Tomlinson J, Zhelev Z, Patterson A, et al (In Press). Exploring reasons for variation in ordering thyroid function tests in primary care: a qualitative study. Quality in Primary Care, 22, 256-261. Abstract.
De Bell S, Zhelev Z, Shaw N, Bethel A, Anderson R, Thompson Coon J (In Press). Remote monitoring for long-term physical health conditions: an evidence and gap map. NIHR Journals Library Publications
Zhelev Z, Peters J, Rogers M, Allen M, Kijauskaite G, Seedat F, Wilkinson E, Hyde C (2023). Test accuracy of artificial intelligence-based grading of fundus images in diabetic retinopathy screening: a systematic review. J Med Screen, 30(3), 97-112. Abstract.  Author URL.
Thompson G, Zhelev Z, Hunt H, Hyde C (2022). It was not easy to identify the study design from the title and abstract of articles indexed as diagnostic (test) accuracy studies in EMBASE in 2012 and 2019. J Clin Epidemiol, 144, 102-110. Abstract.  Author URL.
Ohtake H, Terasawa T, Zhelev Z, Iwata M, Rogers M, Peters JL, Hyde C (2022). Serial high-sensitivity cardiac troponin testing for the diagnosis of myocardial infarction: a scoping review. BMJ Open, 12(11), e066429-e066429. Abstract.
Allen M, James C, Frost J, Liabo K, Pearn K, Monks T, Zhelev Z, Logan S, Everson R, James M, et al (2022). Using simulation and machine learning to maximise the benefit of intravenous thrombolysis in acute stroke in England and Wales: the SAMueL modelling and qualitative study. Health and Social Care Delivery Research, 10(31), 1-148. Abstract.
Thompson G, Zhelev Z, Peters J, Khalid S, Briscoe S, Shaw L, Nunns M, Ludman S, Hyde C (2021). Symptom scores in the diagnosis of pediatric cow's milk protein allergy: a systematic review. Pediatr Allergy Immunol, 32(7), 1497-1507. Abstract.  Author URL.
Rakshasbhuvankar AA, Nagarajan L, Zhelev Z, Rao SC (2020). Amplitude-integrated electroencephalography compared with conventional video-electroencephalography for detection of neonatal seizures. Cochrane Database of Systematic Reviews, 2020(3). Abstract.
Mallett S, Allen AJ, Graziadio S, Taylor SA, Sakai NS, Green K, Suklan J, Hyde C, Shinkins B, Zhelev Z, et al (2020). At what times during infection is SARS-CoV-2 detectable and no longer detectable using RT-PCR-based tests? a systematic review of individual participant data. BMC Medicine, 18(1). Abstract.
Walker GB, Zhelev Z, Henschke N, Fridhandler J, Yip S (2019). Prehospital Stroke Scales as Screening Tools for Early Identification of Stroke and Transient Ischemic Attack. Stroke, 50(10), e285-e286. Author URL.
Zhelev Z, Walker G, Henschke N, Fridhandler J, Yip S (2019). Prehospital stroke scales as screening tools for early identification of stroke and transient ischemic attack. Cochrane Database Syst Rev, 4(4). Abstract.  Author URL.
Olsen M, Zhelev Z, Hunt H, Peters JL, Bossuyt P, Hyde C (2019). Use of test accuracy study design labels in NICE's diagnostic guidance. Diagn Progn Res, 3 Abstract.  Author URL.
Rachuba S, Salmon A, Zhelev Z, Pitt M (2018). Redesigning the diagnostic pathway for chest pain patients in emergency departments. Health Care Management Science, 21(2), 177-191. Abstract.
Chisnell J, Marshall T, Hyde C, Zhelev Z, Fleming LE (2017). A content analysis of the representation of statins in the British newsprint media. BMJ Open, 7(8). Abstract.  Author URL.
Walker GB, Zhelev Z, Frid handler J, Henschke N, Yip S (2017). Abstract TP252: Prehospital Stroke Scales as a Tool for Early Identification of Stroke and Transient Ischemic Attacks: a Cochrane Systematic Review. Stroke, 48(suppl_1).
Fortnum H, Ukoumunne OC, Hyde C, Taylor RS, Ozolins M, Errington S, Zhelev Z, Pritchard C, Benton C, Moody J, et al (2016). A programme of studies including assessment of diagnostic accuracy of school hearing screening tests and a cost-effectiveness model of school entry hearing screening programmes. Health Technol Assess, 20(36), 1-178. Abstract.  Author URL.
Zhelev Z, Abbott R, Rogers M, Fleming S, Patterson A, Hamilton WT, Heaton J, Thompson Coon J, Vaidya B, Hyde C, et al (2016). Effectiveness of interventions to reduce ordering of thyroid function tests: a systematic review. BMJ Open, 6(6). Abstract.  Author URL.
Zhelev Z, Hyde C, Youngman E, Rogers M, Fleming S, Slade T, Coelho H, Jones-Hughes T, Nikolaou V (2015). Diagnostic accuracy of single baseline measurement of Elecsys Troponin T high-sensitive assay for diagnosis of acute myocardial infarction in emergency department: systematic review and meta-analysis. BMJ, 350 Abstract.  Author URL.
Zhelev Z, Hyde C, Fitzgerald JE, Ukoumunne O, Briscoe S, Chisnell J, Grigore B (2015). Tests for screening for hearing loss in children about to start school. Cochrane Database of Systematic Reviews, 2015(11). Abstract.
Hunt HA, Stanworth S, Curry N, Wolley T, Cooper C, Ukoumunne O, Zhelev Z, Hyde C (2015). Thromboelastography (TEG) and rotational thromboelastometry (ROTEM) for trauma-induced coagulopathy in adult trauma patients with bleeding. Cochrane Database of Systematic Reviews 2015(2).
Walker G, Yip S, Zhelev Z, Henschke N (2014). Prehospital stroke scales as screening tools for early identification of stroke and transient ischemic attack. Cochrane Database of Systematic Reviews, 2014(12). Abstract.
Zhelev Z, Garside R, Hyde C (2013). A qualitative study into the difficulties experienced by healthcare decision makers when reading a Cochrane diagnostic test accuracy review. Syst Rev, 2 Abstract.  Author URL.
Freeman, P. Taylor, A. Proykov, T. (2003). The reform of child welfare services in Bulgaria. Journal of Social Work in Europe, 10(3).
Zhelev Z, Bakalova R (2002). Effect of vitamins E and C on transplant-associated atherosclerosis. Lancet, 360(9331). Author URL.

Conferences

Zhelev Z, Patel K, Youngman E, Peters J, Lowe J, Cooper C, Shields B, Hattersley A, Hyde C (2016). Autoantibody status as a predictor of future insulin deficiency in patients with diabetes: a systematic review.  Author URL.
Rachuba S, Salmon A, Zhelev Z, Pitt M (2016). Simulating single test rule-out strategies for chest pain patients at emergency departments.  Abstract.

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Teaching

Supervision of undergraduate student projects and MSc dissertations

Supervision of postgraduate students

“Making sense of evidence” modules for 1st and 2nd year BMBS students

Structured Small Group Learning sessions as part of the Integrated Human Physiology module (CSC1005; 2018 – 2021)

Evaluation of medical tests – workshops for healthcare professionals, post-graduate students and other researchers

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Supervision / Group

Postgraduate researchers

  • Hirotaka Ohtake, Accuracy of serial high-sensitivity troponin for the diagnosis of myocardial infarction

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