'One-stop shopping' for information on conducting systematic reviews and meta-analysis in animal agriculture and veterinary medicine.

Abstract

This issue of Zoonoses and Public Health is devoted to systematic reviews in animal agriculture and veterinary medicine. Systematic reviews are an approach to research synthesis used to answer a specific question that relates to a clinical or policy question (EFSA, 2010). Although systematic reviews are increasingly being used in veterinary medicine and animal agriculture, the methods employed for systematic reviews for individual patient care often require some modification for the unique aspects of animal populations. Thus, the articles in this issue describe not only how to conduct a systematic review, but also highlight issues specific to their use in veterinary medicine and animal agriculture. While systematic reviews can be used to address different types of questions (interventions, prevalence estimates and diagnostic test accuracy), the focus of this issue is on systematic reviews of intervention questions. The first paper provides an overview of the process of systematic reviews, as well as overviewing their current and historical use in human and veterinary medicine. The next two papers focus on the evidentiary value of different study designs (paper 2) and the details of clinical trial design in veterinary medicine (paper 3). Clinical trials are the most common type of study design included in systematic reviews. The final three papers provide detail on how to conduct each step of the systematic review, from formulating the question to interpreting the results. The chapter on meta-analysis (the statistical combination of data obtained from multiple primary research studies) provides basic coding for conducting a meta-analysis using the free software r (version 3.0.2, R Foundation for Statistical Computing, Vienna, Austria). The issue is intended as a resource for those seeking to understand systematic reviews and meta-analysis to critically read them or to use the results for clinical or policy decision-making. Researchers or graduate students wanting to learn how to conduct systematic reviews and meta-analysis also may find the issue to be a valuable resource. In addition to the descriptions of the process, each chapter provides references to additional literature for learning more about each topic. Finally, educators teaching the process and methods of systematic reviews and meta-analysis may wish to use all or part of this issue as teaching material. We are grateful to Zoonoses and Public Health for the opportunity to publish this group of papers together as a special issue. In particular, our heartfelt thanks to Dr. Mary Torrence, Editor in Chief, who has been a major supporter of our work on systematic reviews since we began to explore this area.