PhD M.M.G. Leeflang

Associate Professor
Main activities
Education, Research
Systematic reviews, Research Methodology, Meta-analyses
Focus of research

Methodology of systematic reviews and meta-analyses of diagnostic tests.

Key publications
  • Leeflang M. M. G. Systematic reviews and meta-analyses of diagnostic test accuracy Clinical microbiology and infection 2014;20 (2):105-113 [PubMed]
  • Ochodo Eleanor A., de Haan Margriet C., Reitsma Johannes B., Hooft Lotty, Bossuyt Patrick M., Leeflang Mariska M. G. Overinterpretation and misreporting of diagnostic accuracy studies: evidence of "spin" Radiology 2013;267 (2):581-588 [PubMed]
  • Leeflang Mariska M. G., Rutjes Anne W. S., Reitsma Johannes B., Hooft Lotty, Bossuyt Patrick M. M. Variation of a test's sensitivity and specificity with disease prevalence CMAJ 2013;185 (11):E537-E544 [PubMed]
  • Ochodo Eleanor A., Reitsma Johannes B., Bossuyt Patrick M., Leeflang Mariska M. G. Survey revealed a lack of clarity about recommended methods for meta-analysis of diagnostic accuracy data Journal of clinical epidemiology 2013;66 (11):1281-1288 [PubMed]
  • Wang Junfeng, Bossuyt Patrick, Geskus Ronald, Zwinderman Aeilko, Dolleman Madeleine, Broer Simone, Broekmans Frank, Mol Ben Willem, Leeflang Mariska Using individual patient data to adjust for indirectness did not successfully remove the bias in this case of comparative test accuracy Journal of clinical epidemiology 2015;68 (3):290-298 [PubMed]
All Publications
Curriculum Vitae

2002 – 2003 Professional training Veterinary Medicine (Medical training internship).
Graduated as a large animal veterinarian in November 2003.
2000 – 2002 Excellent track research internship, Veterinary Faculty, Utrecht University.
1996 – 2000 MSc Veterinary Medicine, Veterinary Faculty, Utrecht University.

Department of Clinical Epidemiology, Biostatistics and Bioinformatics, University of Amsterdam:
Period: July 2008 – present
Position: Epidemiologist, researcher
Tasks involve: Methodological research in diagnostic test evaluation and diagnostic meta-analysis.

Continental Europe Regional Support Unit for Cochrane diagnostic test accuracy reviews:
Period: February 2007 – 2010
Position: Epidemiologist
Tasks involve: Providing support for Cochrane Review Groups and review authors who are based on the European continent and involved in the preparation and publication of diagnostic test accuracy reviews. Mariska is responsible for the training courses and the website of the DTA working group. Besides that she has tested the RevMan 5 software and assists authors with meta-analyses, methodology, searching.

Epidemiology Unit, Royal Tropical Institute, Amsterdam
Period: April 2008 – January 2010
Position: Epidemiologist, providing methodological support
Tasks involve: Preparation of and presenting epidemiology lectures in Rwanda and Amsterdam and assisting with research methodology for different diagnostic test evaluation projects. Also coordinator of training in diagnostic research methods for KIT-BR staff members.

PhD, University of Amsterdam:
Period: February 2004 – July 2008
Department: Clinical Epidemiology, Biostatistics and Bioinformatics, Academic Medical Center (in cooperation with the Dutch Cochrane Centre)
Supervisors: prof.dr. Patrick Bossuyt, dr. Rob Scholten, dr. Hans Reitsma
Title: Systematic Reviews of Diagnostic Test Accuracy
Graduation: 1st July, 2008.

2016 – now:  Coordinator of the Honours program of the AMC, a highly ambitious program for outstanding medical students, bachelor level and master level.
2015 – now:  Guest Lecturer in Master programs of the University of Birmingham and the Paris Descartes University in Paris.
2011 – now:  For the AMC Graduate School: five-day course on Test Evaluation for PhD students.
2007 – 2010:  For the Royal Tropical Institute (KIT) in Amsterdam: Lecturer Evidence-Based Medicine and Diagnostic test evaluations at the Medical School of Kigali, Rwanda; and coordinator of an internal training program on test evaluation for employees of the KIT.

2016 Two days lecturing Cochrane diagnostic reviews for the University of Tehran, Iran.
2015 Keynote speaker at the expert meeting on Lyme disease at the European Centre for Disease Control and Prevention (ECDC), Stockholm, Sweden.
2013 Keynote speaker at the autumn meeting of the British Society for Parasitology, Liverpool.
2009 & 2011 Lectures for the University of Stellenbosch, Cape Town, South Africa.
2010 One-day lecturing on diagnostic accuracy reviews at McGill University, Montreal, Canada.
2010 Invited presentation at the Gates’ Foundation, Seattle, USA; about TB testing.
2009 Two-day lecturing on Cochrane diagnostic reviews for Thai contributors, Bangkok.
2008 Invited presentation for the 5th Asian-Pacific Conference on EBM, Lanzhou, China.

2004 – 2014 For Cochrane©: coordinator of workshops about diagnostic review methodology at all Cochrane Colloquia from 2004 to 2014.
2011 Member of the organizing committee for the yearly meeting of the Dutch Working Group for Epidemiology research (WEON), IJmuiden, The Netherlands
2011 Organizer of a two-day international workshop on comparative accuracy and network meta-analyses in Amsterdam.

2016 – now Associate Editor for the BMC Diagnostic and Prognostic Research, a new journal.
2011 – now Board member of The Netherlands Epidemiological Society.
2011 – now Associate Editor for the BMC Medical Research Methodology. (IF 3)
2008 – now Editor for the Cochrane Diagnostic Test Accuracy Editorial Team. (IF 6)
2004 – now Peer reviewer for a number of scientific journals, among which the Journal of Clinical Epidemiology, The BMJ and Scientific Reports (open access journal from Nature).

2016 – 2020 MiRoR (Methods in Research of Research); H2020, Marie Curie Innovative Training Network (European Joint Doctorate). Co-applicant and supervisor of two PhD students.
2014 – 2016 Methods Innovation Fund, Plain Language Summaries for Cochrane Diagnostic test accuracy reviews (50,000 euros); co-applicant and supervisor of post-doc.
2010 – 2014 Veni, The Netherlands Organization for Scientific Research (NWO); 250.000 euros
2011 – 2016 FP7 program, DECIDE; co-applicant and supervisor of one PhD student.
2012 – 2014 Evaluation of serology for Lyme disease; ECDC; 50.000 euros; co-applicant and lead-author.

2016 Aspasia – to promote excellent female researchers to either an associate or full professorship; The Netherlands Organization for Scientific Research (NWO).
2010 VENI - highly competitive scheme from The Netherlands Organization for Scientific Research (NWO); project 916.10.034

2017 - now: AMC Program Lead APH Methodology programme

2013 – now: Board member of the Graduate School of the AMC, The Netherlands.

2009 – now: Member of the Methods Executive of Cochrane©

Research programmes

PhD M.M.G. Leeflang (Systematic Reviews and Meta-analyses of Diagnostic Tests)

Evidence-based diagnosis and shared decision making in the diagnostic process start with thinking about what evidence is needed to inform patients, clinicians and policy makers about the performance, consequences and added value of diagnostic testing. At the cornerstone of evidence-based medicine are systematic reviews and meta-analyses. This research line focuses on the complete range of diagnostic tests (questionnaires, biomarkers, imaging, etc) and on the complete review process: from review question via type of studies to be included, search strategies, quality assessment, meta-analysis, investigation of heterogeneity and interpretation of the results. It does not focus on the question whether a particular test is valid for a particular disease, but it focuses on the methodological questions behind it: how to decide that a test is valid; how to compare different tests; is the test with the higher odds ratio always better? We also focus on the review process: is it necessary to retrieve every possibly relevant paper for the meta-analysis; how can we incorporate quality assessment in meta-analyses, etc.

In the future, I will specifically focus on (1) comparative accuracy reviews; (2) research integrity and reproducibility in diagnostic reviews; and (3) understanding of patients and public. Comparative accuracy reviews try to answer the question whether one test is more accurate than another. My hypothesis is that this is in fact a causal question, for which considerations about confounding may be important. Research integrity refers to the condcut of (in my case) accuracy studies and accuracy reviews. We are not sure whether there is a thing like publication bias in diagnostic systematic reviews, or whether and how conflicts in interest play a role. Lastly, the understanding and use of testing by patients and public is something to investigate: are patients able to make well-informed choices about diagnostics?

MSc R. Spijker

Prof. PhD P.M.M. Bossuyt (BIomarker and Test Evaluation program (BITE))