Community-acquired pneumonia (CAP) is common and is associated with significant morbidity, mortality and financial burdens. Incidence rates in Finland and the United States have been reported at 12/1000 patients/year; elderly people are particularly susceptible, with an annual incidence of over varies predictably with individual clinical characteristics . Clinical and radiographic features are not consistently reliable in determining the causative microorganism , necessitating initial empirical antimicrobial therapy. Selection of initial therapy may be assisted by empirical antibacterial treatment guidelines . Recent guidelines recommend respiratory quinolones (RQs) – levofloxacin, gatifloxacin and moxifloxacin – in several settings . These agents provide an appealing choice in the therapy of CAP because they offer effective single-agent coverage for Streptococcus pneumoniae, most relevant Gram-negative organisms and atypical pathogens.
Prospective trials assessing the impact of guideline adherence on clinical outcomes have not been performed, but observational studies of previous guidelines for the treatment of CAP have generally not shown that adherence produced significant improvements in clinical outcomes . A more recent study found a lower mortality rate in elderly inpatients treated with regimens that included coverage for atypical organisms , but use of the more recent guidelines , which recommend RQs, has not been well studied. A study of a critical pathway, which included the RQ levofloxacin and multiple clinical interventions, found similar clinical outcomes and a reduction in institutional resource utilization in the intervention institutions . Given the study design, it was difficult to distinguish the effects of the antibiotic therapy from the clinical interventions included in the critical pathway. Authors Marras and Chan found guideline utilization to be high in a previous review at their institution , but have little information on adherence to more recent guidelines.
We performed a retrospective cohort study to assess several issues. First, we studied the implementation of antimicrobial guidelines, comparing secular periods before and after their revision. Second, we searched for associations between guideline adherence and clinical outcomes or antimicrobial costs in both the early and recent cohorts. Third, we compared outcomes between guideline-adherent cases in the early and recent cohorts. Fourth, we assessed differences in outcomes between patients treated with various empirical antimicrobials.