Purpose: The American Thoracic Society recommends that all community-acquired pneumonia patients admitted to the hospital be treated for atypical pathogens (e.g. Legionella or Legionnaire’s). The purpose of this decision model is to validate these guidelines.
Method: A decision tree with an embedded Markov chain evaluated the two alternative management strategies impacted by the ATS guidelines. One strategy is to cover all patients for atypical pathogens; another is to cover patients without severe disease with non-atypical coverage (e.g., penicillin), then test for the presence of atypical pathogens and switch medications if needed. Data from an international database of community-acquired pneumonia patients was used to establish baseline estimates in the model. Preference data was estimated from previous outcome studies found in the literature. Cost data was based on ICD-9 codes and Medicare reimbursement rates. Sensitivity analyses were done to test assumptions in the model and the decision’s robustness.
Result: Atypical coverage increases costs but improves outcomes by reducing the time to clinical stability, length of hospital stays and mortality rates. However, as the global prevalence of atypical pathogens in the natural reservoir is lower than a baseline of 22%, the recommendation of coverage switches to a test-and-treat strategy in which the patients who are positive for atypical pathogens are given drugs responsive to atypical pathogens; otherwise, for patients with test results negative for atypical pathogens, non-atypical coverage is continued. To maximize efficiency of health resources, developing countries should attempt to establish regional baselines for the prevalence of atypical pathogens before implementing the ATS guidelines.
Conclusion: This decision analysis illuminates the need to establish and monitor the prevalence of atypical pathogens as the source of community-acquired pneumonia. Atypical and non-atypical coverage is efficient when the prevalence exceeds 22% but less so when rates are low. The impact of community-acquired pneumonia on quality of life, mortality and resource use is significant and requires careful decision making by policy makers.
Candidate for the Lee B. Lusted Student Prize Competition