PROBAST Steering Group
Members of the PROBAST Group who authored this work: Robert F. Wolff, MD (Kleijnen Systematic Reviews, York, United Kingdom); Prof. Karel G.M. Moons, PhD (Julius Center for Health Sciences and Primary Care and Cochrane Netherlands, University Medical Center (UMC) Utrecht, Utrecht University, Utrecht, the Netherlands); Prof. Richard D. Riley, PhD (Keele University, Keele, United Kingdom); Penny F. Whiting, PhD (University Hospitals Bristol NHS Foundation Trust and University of Bristol, Bristol, United Kingdom); Marie Westwood, PhD (Kleijnen Systematic Reviews, York, United Kingdom); Prof. Gary S. Collins, PhD (Centre for Statistics in Medicine, Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, University of Oxford, Oxford, United Kingdom); Johannes B. Reitsma, MD, PhD (Julius Center for Health Sciences and Primary Care and Cochrane Netherlands, UMC Utrecht, Utrecht University, Utrecht, the Netherlands); Prof. Jos Kleijnen, MD, PhD (Kleijnen Systematic Reviews, York, United Kingdom, and School for Public Health and Primary Care, Maastricht University, Maastricht, the Netherlands); and Sue Mallett, DPhil (Institute of Applied Health Research, University of Birmingham, Birmingham, United Kingdom).
PROBAST Delphi Group
Members of the PROBAST group who were nonauthor contributors: Prof. Doug Altman, PhD (Centre for Statistics in Medicine, Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, University of Oxford, Oxford, United Kingdom); Prof. Patrick Bossuyt, PhD (Division of Clinical Methods & Public Health, University of Amsterdam, Amsterdam, the Netherlands); Prof. Nancy R. Cook, ScD (Brigham and Women's Hospital, Boston, Massachusetts); Gennaro D'Amico, MD (Ospedale Vincenzo Cervello, Palermo, Italy); Thomas P.A. Debray, PhD, MSc (Julius Center for Health Sciences and Primary Care and Cochrane Netherlands, UMC Utrecht, Utrecht University, Utrecht, the Netherlands); Prof. Jon Deeks, PhD (Institute of Applied Health Research, University of Birmingham, Birmingham, United Kingdom); Joris de Groot, PhD (Philips Image Guided Therapy Systems, Best, the Netherlands); Emanuele di Angelantonio, PhD, MSc (Department of Public Health and Primary Care, University of Cambridge, Cambridge, United Kingdom); Prof. Tom Fahey, MD, MSc (Royal College of Surgeons in Ireland, Dublin, Ireland); Prof. Frank Harrell, PhD (Department of Biostatistics, Vanderbilt University, Nashville, Tennessee); Prof. Jill A. Hayden, PhD (Department of Community Health and Epidemiology, Dalhousie University, Halifax, Nova Scotia, Canada); Martijn W. Heymans, PhD (Department of Epidemiology and Biostatistics, Amsterdam Public Health Research Institute, Vrije Universiteit UMC, Amsterdam, the Netherlands); Lotty Hooft, PhD (Julius Center for Health Sciences and Primary Care and Cochrane Netherlands, UMC Utrecht, Utrecht University, Utrecht, the Netherlands); Prof. Chris Hyde, PhD (Institute of Health Research, University of Exeter Medical School, Exeter, United Kingdom); Prof. John Ioannidis, MD, DSc (Meta-Research Innovation Center at Stanford, Stanford University, Palo Alto, California); Prof. Alfonso Iorio, MD, PhD (Department of Health Research Methods, Evidence, and Impact, McMaster University, Hamilton, Ontario, Canada); Stephen Kaptoge, PhD (Department of Public Health and Primary Care, University of Cambridge, Cambridge, United Kingdom); Prof. André Knottnerus, MD, PhD (Department of Family Medicine, Maastricht University, Maastricht, the Netherlands); Mariska Leeflang, PhD, DVM (Department of Clinical Epidemiology, Biostatistics and Bioinformatics, University of Amsterdam, Amsterdam, the Netherlands); Frances Nixon, BSc (National Institute for Health and Care Excellence, Manchester, United Kingdom); Prof. Pablo Perel, MD, PhD, MSc (Centre for Global Chronic Conditions, London School of Hygiene and Tropical Medicine, London, United Kingdom); Bob Phillips, PhD, MMedSci (Centre for Reviews and Dissemination, York, United Kingdom); Heike Raatz, MD, MSc (Kleijnen Systematic Reviews, York, United Kingdom); Rob Riemsma, PhD (Kleijnen Systematic Reviews, York, United Kingdom); Prof. Maroeska Rovers, PhD (Departments of Operating Rooms and Health Evidence, Radboud UMC, Nijmegen, the Netherlands); Anne W.S. Rutjes, PhD, MHSc (Institute of Social and Preventive Medicine and Institute of Primary Health Care, University of Bern, Bern, Switzerland); Prof. Willi Sauerbrei, PhD (Institute of Medical Biometry and Statistics, Faculty of Medicine and Medical Center, University of Freiburg, Freiburg, Germany); Stefan Sauerland, MD, MPH (Institute for Quality and Efficiency in Healthcare, Cologne, Germany); Fülöp Scheibler, PhD, MA (UMC Schleswig-Holstein, Kiel, Germany); Prof. Rob Scholten, MD, PhD (Julius Center for Health Sciences and Primary Care and Cochrane Netherlands, UMC Utrecht, Utrecht University, Utrecht, the Netherlands); Ewoud Schuit, PhD, MSc (Julius Center for Health Sciences and Primary Care and Cochrane Netherlands, UMC Utrecht, Utrecht University, Utrecht, the Netherlands); Prof. Ewout Steyerberg, PhD (Department of Public Health, Erasmus UMC, Rotterdam, and Department of Biomedical Data Sciences, Leiden UMC, Leiden, the Netherlands); Toni Tan, MSc (National Institute for Health and Care Excellence, Manchester, United Kingdom); Gerben ter Riet, MD, PhD (Department of General Practice, University of Amsterdam, Amsterdam, the Netherlands); Prof. Danielle van der Windt, PhD (Centre for Prognosis Research, Keele University, Keele, United Kingdom); Yvonne Vergouwe, PhD (Department of Public Health, Erasmus UMC, Rotterdam, the Netherlands); Andrew Vickers, PhD (Memorial Sloan-Kettering Cancer Center, New York, New York); and Angela M. Wood, PhD (Department of Public Health and Primary Care, University of Cambridge, Cambridge, United Kingdom).
The Delphi group members made substantial contributions to the conception and design, acquisition of data, or analysis and interpretation of the data; they drafted the article or revised it critically for important intellectual content; and they approved the final version to be published.
Response to: Feasibility of using PROBAST to assess bias and applicability of dementia prediction models
In fact, we are pleasantly surprised to see that PROBAST, which has only been published recently, is already been used.(3,4) Furthermore, we are pleased to see that the comment highlighted the usefulness of two key elements of PROBAST:
1. Four domains (participants, predictors, outcome, and analysis) are rated as part of a PROBAST assessment, allowing users to pinpoint shortcomings in the methodology of the underlying study reporting the development and/or validation of a prediction model
2. PROBAST allows the assessment of the risk of bias and applicability of a study. The comment illustrated that PROBAST appears to have been a useful tool in assessing the five models investigated by Licher et al., i.e. identifying a prediction model study which was rated as low risk of bias and low concerns regarding applicability.
On www.probast.org, we will list this study as an example of the use of PROBAST. The website also presents other details relevant to prediction research, e.g. information on workshops, details on relevant research initiatives as well as the current version of the PROBAST tool.
References:
1. Licher S, Yilmaz P, Leening MJG, Wolters FJ, Vernooij MW, Stephan BCM, et al. External validation of four dementia prediction models for use in the general community-dwelling population: a comparative analysis from the Rotterdam Study. European Journal of Epidemiology. 2018;33(7):645-55.
2. Licher S, Leening MJG, Yilmaz P, Wolters FJ, Heeringa J, Bindels PJE, et al. Development and validation of a dementia risk prediction model in the general population: an analysis of three longitudinal studies. Am J Psychiatry. 2018. Epub Ahead of Print.
3. Wolff RF, Moons KGM, Riley RD, Whiting PF, Westwood M, Collins GS, Reitsma JB, Kleijnen J, Mallett S, PROBAST Group. PROBAST: a tool to assess the risk of bias and applicability of prediction model studies. Ann Intern Med 2019;170(1):51-58. Freely available from: http://annals.org/aim/fullarticle/2719961/probast-tool-assess-risk-bias-applicability-prediction-model-studies
4. Moons KGM, Wolff RF, Riley RD, Whiting PF, Westwood M, Collins GS, Reitsma JB, Kleijnen J, Mallett S. PROBAST: a tool to assess the risk of bias and applicability of prediction model studies: explanation and elaboration. Ann Intern Med 2019;170(1):W1-W33. Freely available from: http://annals.org/aim/fullarticle/2719962/probast-tool-assess-risk-bias-applicability-prediction-model-studies-explanation
Disclosures: See disclosure information in the PROBAST article
Feasibility of using PROBAST to assess bias and applicability of dementia prediction models
Following PROBAST, we selected dementia prediction models that have been developed and externally validated to identify individuals at high risk in the general population in order to facilitate targeted preventive efforts (Steps 1 and 2). We systematically examined the risk of bias and concerns regarding the applicability for each of these models (Step 3). Based on a previously published literature search on dementia models (updated until Jan 1st, 2019) (4, 5), we identified five validated models (Cardiovascular Risk Factors, Aging, and Incidence of Dementia; ANU-Alzheimer's Disease Risk Index; Brief Dementia Screening Indicator; Dementia Risk Score; and The Rotterdam Study model). PROBAST identified high risk of bias in three of these models that could compromise their internal validity but raised low concern regarding applicability (Step 4). For one model, we identified both high risk of bias and high concerns regarding applicability. A single model met all criteria, indicating that there were low concerns regarding risk of bias and applicability. Of the four domains in PROBAST (i.e. participants, predictors, outcome, and analysis), a high risk of bias in the analysis domain was common, being present in four of the five models. Detailed PROBAST assessments for each of these models are available upon request.
We conclude that PROBAST facilitates systematic examination and summarizing of the quality and applicability of prediction models, and thereby facilitates selection of prediction models for clinical use. Importantly, our application of PROBAST revealed methodological shortcomings for the majority of dementia prediction models, which may compromise reliable risk estimation in clinical practice. These findings highlight that rigorous external validation of prediction models is not sufficient to guarantee internal validity.
References
1. Wolff RF, Moons KGM, Riley RD, Whiting PF, Westwood M, Collins GS, et al. PROBAST: a tool to assess the risk of bias and applicability of prediction model studies. Ann Intern Med. 2019;170(1):51-8.
2. Tang EY, Harrison SL, Errington L, Gordon MF, Visser PJ, Novak G, et al. Current developments in dementia risk prediction modelling: an updated systematic review. Plos One. 2015;10(9):e0136181.
3. Hou XH, Feng L, Zhang C, Cao XP, Tan L, Yu JT. Models for predicting risk of dementia: a systematic review. J Neurol Neurosurg Psychiatry. 2018. Epub Ahead of Print.
4. Licher S, Yilmaz P, Leening MJG, Wolters FJ, Vernooij MW, Stephan BCM, et al. External validation of four dementia prediction models for use in the general community-dwelling population: a comparative analysis from the Rotterdam Study. European Journal of Epidemiology. 2018;33(7):645-55.
5. Licher S, Leening MJG, Yilmaz P, Wolters FJ, Heeringa J, Bindels PJE, et al. Development and validation of a dementia risk prediction model in the general population: an analysis of three longitudinal studies. Am J Psychiatry. 2018. Epub Ahead of Print.
Disclosures: We declare no potential financial conflicts of interest. The literature search that was done for this work also identified one model that that has been developed and validated by the authors themselves.