All three sites have general internal medicine (GIM) clinical teaching units into which patients with CAP are generally admitted and managed. The source of referrals is almost exclusively from the emergency department (ED), to which patients either self-refer or are sent by primary care practitioners. If the ED physician decides that the patient requires admission or to see a specialist, a consultation from the GIM service is obtained. The GIM team makes the admission decision and all inpatient care decisions.
The study period (November 1997 to June 2000) was divided into early and recent cohort periods, defined by the contemporary version of antibiotic guidelines endorsed at the University of Toronto. The early cohort period was from November 1997 to October 1998 (1993 Canadian Thoracic and Infectious Diseases Societies’ guidelines ), and the recent cohort period was from November 1998 to June 2000 (1998 Infectious Diseases Society of America [IDSA] guidelines ). The study period began one year before our institutions endorsed the first widely publicized CAP guidelines recommending RQs , through the revision of institutional recommendations and addition of a RQ (levofloxacin) to the formularies. The duration of the study period was selected to capture a significant number of CAP cases treated according to both the early and recent guidelines. The appropriate institutional research ethics review boards approved the protocol.