My Background

I worked in primary care as a GP in Hertfordshire for 23 years, with a particular interest in applying evidence in practice. In 1999 my practice was awarded Beacon status for successfully reducing antibiotic prescribing in children with ear infections. My website includes an online calculator which will create Cates plots ( ‘smiley face' plots that visually communicate the risks and benefits of treatment). The plots help explain how the effects of treatment apply to high-risk and low-risk patients, and how benefits and risks of treatments can be compared. These plots have been adopted as part of the Patient Decision Aids initiative from the National Prescribing Centre (NPC) in Liverpool and available on the NPC legacy website.

I started as a systematic reviewer with Cochrane Airways at St George's in 1995 and authored a number of systematic reviews summarising the risks and benefits of a variety of inhaled treatments and vaccinations for asthma and COPD. My first review compared spacers to nebulisers for delivering inhaled treatment to people with acute asthma, and spacers have now become the recommended delivery method for children in many asthma guidelines, such as the SIGN/BTS Asthma Guideline. I have been co-ordinating Editor from 2003 to 2020.

Evidence Based Medicine

I am familiar with the principles of Evidence Based Medicine (EBM), and tried to carry them out in my practice.  I have learnt from practical experience some of the limitations of EBM as well as the potentials!  As a user of the Cochrane Library (as well as a contributor) I am familiar with the practicalities of posing an answerable question, seeking out reliable evidence and assessing it.  This work together with a description of our change in prescribing are described on my web-site at www.nntonline.net .  This is also the home of a collection of articles that I have written on various aspects of Evidence Based Medicine and Statistics.

Critical Appraisal

Carrying out Systematic Reviews has taught me appraisal skills not only in the field of primary research papers (which have to be graded according to their methodological quality) but also in terms of the review process itself.    I have a particular interest in the methodology of meta-analysis and associated confidence intervals, and I am concerned that the current increased usage of “Numbers Needed to Treat” is not at the expense of rigour in its calculation. I recognise that the biggest challenge in presentation of evidence is to find simple and understandable ways to present quite complex data, and have worked with my son (Peter Cates) to develop graphical methods to get the messages across to patients and practitioners. This is now available from my website as free software (Visual Rx) which will generate Cates Plots to show the absolute impact of summary Odds Ratios and Relative Risks. These have been used by the National Prescribing Center in the UK to illustrate Patient Information Leaflets for Primary Care.

I have written for Pulse, Prescriber and Update about systematic reviews and other evidence that might be important in daily general practice. This has included a series for the registrar pages of Pulse about statistics (now archived on my web site) , critical appraisal, systematic reviews, use of the Cochrane Library etc.  I have contributed several articles a series for Prescriber on EBM in 2002, and was overall editor for the series. In 2005 I wrote a series of articles about statistics for Update  and these are also archived on my website.

Statistical Methodology

One of my main roles for Cochrane Airways was to oversee the statistical methods used in our systematic reviews and check that the data entered into the reviews is accurate.

I have been an active member of the Statistical Methods Group and the Bias Methods Group of the Cochrane Collaboration.

Research into Statistical Methodology for Systematic Reviews

At the Seventh Cochrane Colloquium in Rome in 1999 I presented an abstract on the methodology of calculating Numbers Needed to Treat from the results of systematic reviews.  I have also written (in conjunction with my son) a software programme (Visual Rx www.nntonline.net ) that will calculate NNT from Pooled Data and display the results graphically.  This has been assessed in an educational context in Canada and used in a research project in the UK. I believe that the use of graphical displays is crucial to promote the understanding of the effects and harms of treatment to a wide audience.

I have contributed to the development of the Risk of Bias 2.0 tool, estimating pairwise variance in meta-analyses of multi-arm trials and use of Minimal Important Differences for continuous outcomes (see publications list).

Cochrane Airways is funded by the National Institute of Health Research (UK)

We work in collaboration with a large group of authors and editors from all over the world.

These currently include:

Professor Anne Chang (Menzies School of Health Research, Charles Darwin University, Australia)

Professor Francine Ducharme (Department of Paediatrics, University of Montreal, Canada)

Dr Mike Greenstone (Castle Hill Hospital, Cottingham, North Humberside, UK)

Associate Professor Anne Holland (La Trobe University Melbourne, Australia)

Mr Toby Lasserson (Cochrane Editorial Unit, 11-13 Cavendish Square London, UK)

Professor Phillippa Poole (University of Auckland, New Zealand)

Associate Professor Milo Puhan (Johns Hopkins Bloomberg School of Public Health, Baltimore, USA)

Professor Brian Rowe (Department of Emergency Medicine, University of Alberta, Edmonton, Canada)

Dr Sally Spencer (Faculty of Health and Medicine, Lancaster University, UK)

Dr Julia Walters (School of Medicine, University of Tasmania, Hobart, Australia)

Professor Haydn Walters (Menzies Research Institute, University of Tasmania, Hobart, Australia)

Dr John White (York District Hospital, UK)

Associate Professor Ian Yang (School of Medicine, University of Queensland, Australia)

Teaching

I run training sessions for Vocational Training Schemes (for the trainers and registrars) on Evidence Base Medicine and Critical Appraisal.  I have also taught attached Medical Students on the same topics.  Since 2001 I have presented at one day training courses in General practice on the use of evidence in practice, and preparing registrars for the statistical questions in the AKT paper of the MRCGP.  These have successfully migrated to an online format in 2020.

I have presented our work on putting evidence into practice as an invited speaker at a day-conference in New York in March 2000 for around 500 primary care practitioners on the judicious use of antibiotics in acute otitis media.

I have given lectures on the principles of Evidence Based Medicine for General Practitioners and have taught primary care professionals at the University of Hertfordshire on their EBM courses. I have also lectured on a pharmacovigilance course at the University and contributed to a teaching video for trainee pharmacists.

I have taught reviewers at Cochrane Workshops on Protocol Development and the use of the Meta-analysis software.  I have also taught sessions on courses for systematic reviewers at Oxford and University College London. I am actively involved in the delivery of  teaching Cochrane methodology in the UK and Ireland.

I have also given presentations to local General Practitioners and nurses in a variety of post-graduate centres in Hertfordshire on topics including Nebulisers and Spacers in acute asthma, changing to CFC-free inhalers, inhaled steroids in chronic obstructive pulmonary disease, the use of antibiotics in otitis media, and pharmacological interventions for ischaemic heart disease.

I have led sessions on the MSc Course on Evidence-Based Medicine at Oxford in 2005 and 2006 and more recently in 2018 for Clinical Pharmacologists in training at their annual conference in London.

I served as a trainer in General Practice for 12 years (1986-98), and acted as a convenor of the local trainers’ group for my final two years as a trainer.