Evidence based public health: A review of the experience of the National Institute of Health and Clinical Excellence (NICE) of developing public health guidance in England

Abstract

This paper describes the application of the principles of evidence based medicine to public health. It recounts the experience of the National Institute for Health and Clinical Excellence in England (NICE) which acquired a remit to develop public health guidance in 2005. Some of the history of the origins of the evidence based approach is described in the writings of Cochrane and others, and the way that this came to be a critical part of the NICE approach to developing clinical cost effectiveness is outlined. The challenge of applying these methods to an evidence base which is social and psychological as well as biomedical is considered. Key problems are identified: the breadth of the evidence base, different analytic levels of explanation, and the length of the causal chain between interventions and outcomes in public health.

Introduction

This paper discusses the challenges that have arisen in applying the principles of evidence based medicine to the development of public health guidance in the National Institute for Health and Clinical Excellence (NICE) in England. Although NICE’s remit for its public health work only extends to England, the idea of applying principles of evidence based clinical medicine to public health problems and then to develop guidance and policy from the evidence was an important experiment. Only the US Center for Disease Control (CDC) Task Force on Community Preventive Services, was doing anything similar when NICE embarked on its public health programme of work. The methodological and practical questions which have arisen as the evidence based approach has been applied in complex areas of public policy, which are described in this paper, have a much wider currency than England or the United Kingdom. The idea of taking an evidence based approach to developing practice and policy in arenas such as transport, education, social welfare, criminal justice for example has international interest. There is an international network called the Campbell Collaboration which is set up to do develop methods and processes to do precisely this for example (http://www.campbellcollaboration.org/). The lessons arising from the English experience of doing this with public health is of relevance to any scientist or policy maker charged with taking forward an evidence based agenda.

The paper considers the questions which have arisen as the successive pieces of public health guidance have been developed since 2005. The authors of the paper have led the public health section at NICE since 2005 and the observations in the paper are derived from the experiences of, and reflections on, developing that public health guidance. In particular the involvement in constructing the scopes for each piece of guidance, commissioning the reviews which underpin the guidance, being present at all of the meetings of the various independent advisory committees which were charged with developing the recommendations in the guidance and dealing with the stakeholders form the basis of the observations presented here. The authors also led on the development of the first edition of the NICE public health process and methods manuals (NICE, 2006) and the revisions to those manuals published in 2009 (NICE, 2009). The views represented here are those of the authors and not of NICE.

NICE was established in 1999 to provide the National Health Service (NHS) in England and Wales (see Electronic Supplementary material) with guidance on the use of new technologies (principally new drugs). Its purpose was to bring an open and transparent approach to scarce resource allocation in an evidence based way. Two questions were paramount; is the drug effective and is its use good value for money for the NHS? NICE’s remit subsequently widened to include the development of clinical guidelines, guidance on the safety and efficacy of surgical and interventional procedures and a range of other outputs (see Electronic Supplementary material).

In April 2005 the production of public health guidance on disease prevention and health promotion was added to the portfolio. The first public health guidance was published in March 2006. Since then guidance ranging from behaviour change, through prevention of teen conceptions and drug misuse to promoting physical activity by environmental interventions has appeared. The definition of public health at NICE is broad and includes a range of activities from the most upstream assessments of national policy to the most downstream such as how a front line doctor or nurse might give advice to an individual on quitting smoking. The guidance NICE produces on public health is aimed at the NHS and also at local government, the education sector, the private and voluntary sectors, government departments and the public. It is concerned with preventing disease and promoting health (see Electronic Supplementary material). The questions which the public health guidance considers are, in essence, the same as those of the appraisal of drugs – is the public health action effective and is its deployment good use of public funds? The public health project at NICE used the platform of established NICE procedures for conducting technology appraisals (assessing the clinical cost effectiveness of new drugs) and developing clinical guidelines (providing recommendations for the care of people with particular clinical conditions) as the basis for developing its initial public health methods (NICE, 2006). It was recognised at the outset that the clinical methods would have to evolve at NICE to deal with public health evidence. Methods which had been constructed initially to assess the clinical cost effectiveness of one drug against another would certainly require some amendment to work for problems like finding optimal ways of delivering needles and syringes to illicit drug users to prevent hepatitis or developing guidance on promoting physical activity by giving people pedometers for example.

At the epicentre of assessments of clinical effectiveness is the randomised controlled trial (RCT). It was understood when the public health work began at NICE that public health questions are only sometimes answered by RCTs and that evidence drawn from other methods and designs would have to be appraised. It was recognised too that the data and evidence that would be drawn upon in the public health work would be broad and go beyond medical science to include the social sciences. It was assumed that NICE’s public health endeavors would push at the boundaries of the evidence based approach. And so it has done and the methods have evolved (NICE, 2009).