Objective: To determine the effectiveness and costs of alternative management strategies for patients infected with the human immunodeficiency virus (HIV) who present with pulmonary symptoms.
Design: Decision analysis comparing initial testing (arterial blood gas analysis, induced sputum analysis, or bronchoscopy with bronchoalveolar lavage) with empiric antibiotics (trimethoprim-sulfamethoxazole or erythromycin). Subsequent steps in management are detailed based on the results of initial management. Patients were stratified by initial CD4 lymphocyte count (less than 200/mm3, 200-500/mm3, or greater than 500/mm3) and results of chest radiography.
Setting: Hypothetical.
Measurements and main results: The estimated levels of effectiveness among strategies were relatively similar, but costs varied markedly. If potentially reasonable strategies are defined as those that have incremental cost-effectiveness ratios below $50,000 per quality-adjusted life year (QALY), the recommended strategies would be: for patients at highest risk for Pneumocystis carinii pneumonia (PCP), with a probability of PCP above 30% (CD4 less than 200/mm3 and abnormal chest radiograph or prior history of PCP), begin with induced sputum analysis ($34,174/QALY); for intermediate-risk patients, with a probability of PCP between 6% and 30% (CD4 less than 200/mm3, regardless of chest radiograph; or CD4 200-500/mm3, regardless of chest radiograph findings), begin with arterial blood gas analysis ($4,593 to $8,310/QALY); for low-risk patients, with a probability of PCP below 6% (CD4 greater than 500/mm3, regardless of chest radiograph findings), begin with one week of erythromycin, followed by induced sputum examination if symptoms persist ($675 to $3,306/QALY). For highest-risk patients, if empiric trimethoprim-sulfamethoxazole was considered entirely to be outpatient therapy, it was preferred management if the probability of PCP was above 38%.
Conclusions: The authors conclude that preferred management strategies are determined more by differences in costs than by differences in levels of effectiveness, and that they vary depending on the probability of PCP in definable patient subgroups.