MEDICAL OUTCOMES AND ANTIMICROBIAL COSTS WITH THE USE OF THE AMERICAN-THORACIC-SOCIETY GUIDELINES FOR OUTPATIENTS WITH COMMUNITY-ACQUIRED PNEUMONIA

Context.-The American Thoracic Society (ATS) published guidelines base d on expert opinion and published data-but not clinically derived or v alidated-for treating adult outpatients with community-acquired pneumo nia, Objective.-To compare medical outcomes and antimicrobial costs fo r patients whose antimicrobial therapy was consistent or inconsistent with ATS guidelines, Design.-Multicenter, prospective cohort study. Se tting.-Emergency departments, medical clinics, and practitioner office s affiliated with 3 university hospitals, 1 community teaching hospita l, and 1 health maintenance organization, Participants.-A total of 864 immunocompetent, adult outpatients with community-acquired pneumonia, 546 aged 60 years or younger with no comorbidity and 318 older than 6 0 years or with 1 comorbidity or more. Main Outcome Measures.-Patients ' antimicrobial therapy was classified as being consistent or inconsis tent with the ATS guidelines, Mortality, subsequent hospitalization, m edical complications, symptom resolution, return to work and usual act ivities, health-related quality oi life, and antimicrobial costs were compared among those treated consistently or inconsistently with the g uidelines, Results.-Outpatients aged 60 years or younger with no comor bidity who were prescribed therapy consistent with ATS guidelines (ie, erythromycin with some exceptions) had 3-fold lower antimicrobial cos ts ($5.43 vs $18.51; P<.001) and no significant differences in medical outcomes, Outpatients older than 60 years or with 1 comorbidity or mo re who were prescribed therapy consistent with ATS guidelines (ie, sec ond-generation cephalosporin, sulfamethoxazble-trimethoprim, or beta-l actam and beta-lactamase inhibitor with or without a macrolide) had 10 -fold higher antimicrobial costs ($73.50 vs $7.50; P<.001); despite tr ends toward higher mortality and subsequent. hospitalization, no signi ficant differences in medical outcomes were observed. Conclusion.-Our findings support the use of erythromycin as recommended by the ATS gui delines for outpatients aged 60 years or younger with no comorbidity, Although the antimicrobial therapy recommended in outpatients older th an 60 years or with 1 comorbidity or more is more costly, this observa tional study provides no evidence of improved medical outcomes in the small subgroup who received ATS guideline-recommended therapy.