Welcome! This site is an attempt to share some of the experience that I have gained as a GP in Hertfordshire and a reviewer and editor with the Cochrane Airways Group. It is also the home of Visual Rx (version 4) and Cates plots.

The site also contains a series of articles that I have written for Update in 2005 and Prescriber and Pulse in 2001 on understanding statistics and critical appraisal. There short articles are listed under AKT Statistics and are relevant for anyone revising for the AKT exam who wants to brush up on statistics and critical appraisal.

Evidence Based Health Care starts with the patient in the consulting room, and in my view there is no substitute for good listening to find out the reason for that particular visit, as I have written in an article for Doctor.  However there are questions arising from almost every consultation and some of these can be turned into a four-part question (as described in the EBM handbook by Sackett et al). For those who want to read more about the PICO framework for such questions, please see the article that I wrote for Pulse on asking a good question.

Some years ago we successfully introduced an evidence-based policy to reduce the use of antibiotics in children with acute otitis media and details are available on the Evidence to Change Practice page, including a link to the published report of our change in approach and the resulting change in prescribing in the BMJ. We used a handout to explain the reason for our change; feel free to adapt it for your own use if you wish. The updated evidence from the Cochrane review (2015) is featured here.

Visual Rx is free software that we have created to convert Odds Ratios or Risk Ratios into Numbers Needed to Treat. This was designed to help with the interpretation of results from Systematic Reviews and clinical trials by producing a graphical display (Cates plot) demonstrating the impact of treatment if it were given to 100 people with the relevant condition. The output is also suitable for creating the absolute treatment effects of treatment using different baseline risks (see the Statin Calculator for an example of this) and the output can be used in Cochrane Summary of Findings Tables.

My first Cochrane systematic review (that I continue to update) compared the use of spacers and nebulisers to deliver Beta-agonists in acute asthma. The latest version of the review is available in the Cochrane Library.

I hope this site may serve as a stimulus to others to find answers to day-to-day questions from practice, and will help those who want to understand what to look for when reading articles in medical journals.  Please feel free to email me email
Dr Chris Cates