Book Review

Asthma: Epidemiology, anti-inflammatory therapy and future trends

N Engl J Med 2000; 343:1661-1662November 30, 2000

Article

Asthma: Epidemiology, anti-inflammatory therapy and future trends
(Respiratory Pharmacology and Pharmacotherapy.) Edited by Mark A. Giembycz and Brian J. O'Connor. 206 pp., illustrated. Boston, Birkhauser, 2000. $219. ISBN: 3-7643-5858-0

In the past two decades, enormous advances in molecular biology and immunology have revolutionized our understanding of disease processes. One disease that is better understood as a result of these advances is asthma. Concepts of the physiological processes of airway narrowing and bronchial hyperresponsiveness have been around for some time, but the integration of this knowledge with immunology has unraveled the mechanisms of these events and led to the understanding that asthma is an inflammatory disease. The delineation of the pathways to inflammation has made it possible to conceive of antiinflammatory mechanisms that explain the effectiveness of existing asthma therapies and to develop new agents to inhibit inflammation.

In parallel with the laboratory research that has provided such exciting results, epidemiologists have been conducting detailed longitudinal studies. In the clinical arena, the effectiveness of therapies is now rigorously evaluated in large clinical trials. The results of epidemiologic studies have led to a revision of our notions about the patterns of wheezing illnesses in childhood. Epidemiologic studies of childhood asthma have also generated new hypotheses about the increase in the prevalence of asthma. These hypotheses, in turn, have triggered more research into the mechanisms of asthma. A textbook that attempts to draw together the information generated in this explosion is therefore relevant and timely, if ambitious. Giembycz and O'Connor have assembled an impressive panel of contributors from around the world to produce the 10 chapters that make up Asthma.

The book starts with chapters on the epidemiology of asthma. There is an excellent review of mortality from asthma, which focuses on temporal and geographic trends. Some of these themes are picked up in a subsequent chapter, which addresses the long-term use of β₂-agonists. Most cases of asthma begin in childhood, and the epidemiology of childhood asthma is superbly and comprehensively presented. It was disappointing, however, to see no reference to a series of systematic reviews of passive smoking and childhood respiratory disease, which were published in 1997 and 1998. A chapter on the assessment of airway inflammation uneasily straddles the gap between epidemiology and therapy. It focuses on the examination of induced sputum, with scanty detail concerning other noninvasive methods, such as the measurement of exhaled nitric oxide.

Three chapters discuss therapy with inhaled corticosteroids. The first two present the two sides of the debate about the use of inhaled corticosteroids as first-line agents in children with asthma. The first of these chapters presents the case for such therapy and also provides a wide-ranging review of the topic. There is a much briefer discussion of the case against corticosteroid therapy in the next chapter. This “debating” technique is provocative and works better, I feel, when delivered orally or in the pages of a journal than it does in a textbook. The new science of research synthesis, or systematic reviewing, emphasizes the importance of rigorous methods for the elimination of bias when reviewing clinical research. It thus seems counterproductive to encourage reviewers to adopt opposing stances deliberately. It is left to the third chapter in this group, which addresses future trends in the use of corticosteroids, to provide a balanced perspective.

New antiinflammatory agents have been developed to treat asthma, and they are covered in the final three chapters. All three are superb summaries of the current information about these therapies. The final chapter, on phosphodiesterase inhibitors, provides a succinct summary of the story of theophylline, which parallels the shift in our understanding of the mechanisms underlying asthma.

As it stands, this book seems to be a somewhat eclectic collection of reviews of important aspects of a rapidly moving field, without any overview of the central themes that tie these reviews together. As I have indicated, these themes do exist and could have been presented nicely in an introduction, which the book lacks. An introduction could also have served to fire the imagination of the reader and convey the excitement felt by those who work in this field — an excitement that is apparent in many of the chapters. The book would also have been more cohesive if more careful attention had been paid to areas of overlap between the chapters.

The inclusion of a chapter that described the inflammatory pathways in asthma and outlined the points at which individual therapies are thought to act would have been helpful. Lively cartoons illustrating the myriad interactions involved in these pathways would have enhanced the text and made the chapters on antiinflammatory therapies easier to follow. On the plus side, each chapter is preceded by a list of all its headings and subheadings, which I found very helpful for navigating the book. There is also a useful index at the end.

Rosalind L. Smyth, M.D.
University of Liverpool, Liverpool L12 2AP, United Kingdom