Section 1 focused on how epidemiological methods and knowledge are used in the clinic with individual patients. This section addresses how evidence is used to inform practice more generally.
Chapter 4 details how to find, assess, and summarize existing evidence. The amount of information available to clinicians and to patients continues to grow rapidly and we all need methods to sift and synthesize it. This chapter starts with a very practical introduction to searching the medical literature, using different resources such as online databases and bibliographic software, then introduces the essential elements of critical appraisal and how to assess the quality of papers, finishing with a description of how to conduct a systematic review and meta-analysis.
Chapter 5 turns to the kind of evidence underpinning preventive medicine. In Section 1 we looked at how risk can be communicated and health promotion supported in the clinic, but these are only part of wider approaches to the control of disease in the population. It is often intuitive to target interventions towards those at highest risk, but we also make the case for addressing risk factors across the whole population. Often these ‘high-risk’ and ‘population’ approaches should be undertaken hand in hand. We review the different levels of prevention—primary, secondary, and tertiary—and then provide more detail on preventing non-communicable disease, using the example of cardiovascular disease, followed by prevention of infectious disease, including vaccination. We complete this chapter with an overview of prevention through screening.
Chapter 6 concludes this section with a very practical guide to evaluating clinical practice. Ensuring that practice is carried out effectively is now part of all our roles. Research is essential to informing the evidence base, but most clinicians will be more actively involved in audit. This chapter describes the similarities and differences between research and audit, briefly explains clinical governance and ethics, and then provides a step-by-step guide to audit practice including choice of question and standards, how to choose an appropriate sample, data collection, storage, analysis, and dissemination.