Canadian Guidelines for the Initial Management of Community-Acquired Pneumonia: An Evidence-Based Update by the Canadian Infectious Diseases Society and the Canadian Thoracic Society

Abstract

Community-acquired pneumonia (CAP) remains a serious illness with a significant impact not only on individual patients but also on society as a whole. Guidelines for the initial antibiotic management of CAP were developed in Canada in 1993 and subsequently by the American Thoracic Society (ATS) that same year and by the Infectious Diseases Society of America (IDSA) in 1998 [1–3]. Each of these sets of guidelines has its own strengths and weaknesses, but individually and collectively they have helped to organize and codify our approach to the patient with CAP. Perhaps most important, they have highlighted the weaknesses and deficiencies in this area and have raised important questions for present and future research. As a result of developments in the past several years, it became clear that our guidelines should be updated and revised. This document is a joint effort by the Canadian Infectious Disease Society (CIDS) and the Canadian Thoracic Society (CTS) and we hope that it will be the first of many such collaborations. A committee was established that was composed of members from both the CIDS and CTS, plus additional colleagues from the United States with strong interests in CAP. The members were divided into 3 teams, each of which was responsible for 1 of 3 sections. These were (1) epidemiology, risk factors, and etiology; (2) diagnosis; and (3) treatment. The committee met for 2 days in Toronto in January 1999, and then each team proceeded to develop a draft of its section. These drafts were then circulated among the committee members, and a revised version was sent to colleagues in the United States, Europe, and Israel for review. This document was then finalized on the basis of their input. Relevant articles published during 1966 to the present were retrieved from MEDLINE with use of the MeSH terms “exp pneumonia/,” “community-acquired,” “nursing home,” “human, “random,” “clinical trial,” “exp antibiotics/,” and “English language.” In addition, abstracts from the annual International Conference on Antimicrobial Agents and Chemotherapy and IDSA meetings held in 1997, 1998, and 1999 were reviewed. For the section on epidemiology and etiology, we searched the terms “community-acquired pneumonia” and “etiology” (simultaneously) and found 968 citations. We applied a hierarchical evaluation of the strength of evidence modified from the Canadian Task Force on the Periodic Health Examination [4]. Well-conducted randomized, controlled trials constitute strong or level I evidence; well-designed controlled trials without randomization (including cohort and case-control studies) constitute level II or fair evidence; and expert opinion, case studies, and before-and-after studies are level III (weak) evidence. Throughout these guidelines, ratings appear as roman numerals in parentheses after each recommendation. None of these categories are readily applied to studies of the etiology of pneumonia. Instead, we applied the categories defined by Marston et al. [5] to indicate the degree of certainty that a given etiologic agent has caused the pneumonia: definite, probable, or possible. Unfortunately, most of the studies examined for this document were reported before publication of Marston's article. An examination of the articles on etiology of pneumonia led to a decision to use a small number of articles (for the group of patients requiring admission to the hospital—the largest group) in which the authors used comprehensive methods to try to establish an etiologic diagnosis. It was felt to be important to present the data in tables that allow the reader to see the range of various pathogens identified in each study rather to use a of the of patients on an in or in small of studies, which are reported in their For the section on a of for and were applied for articles used for the of this section. that each on patients with CAP and that the a in the of CAP be in the of the article. articles with patients years, the or individual case studies or studies in this section were in the or in a For the published articles or abstracts on trials CAP were It was that of that were on in data and the of from be to be on level III evidence. with is the of in the United States, and an It for and of each year The for pneumonia are the of In the annual of pneumonia was year were in the group years, In the group years, the was In a study of in et al. reported that the of pneumonia for each year of and the was as as year among patients It was also in this study that in with A pneumonia for in In 2 in Marston et al. [5] found that the of CAP requiring among was The was among and among The was for years, for of and for In a study of in a et al. found that pneumonia an annual of of the developed pneumonia a of the of pneumonia were of of were with a and were have on the of pneumonia in the et al. found that year developed in in the annual was for studies of in and Israel of and study found several risk for pneumonia in in a and with A stu