OBJECTIVES: AECOPD is a leading cause of hospitalization. A valid and easy-to-use risk stratification tool applicable not only for clinical but also economic outcomes would facilitate population-based outcome studies. We sought to validate an AECOPD clinical risk stratification tool previously reported and determine its utility for economic outcomes. METHODS: We analyzed 57,791 AECOPD admissions in 2004-2005 across 191 USA hospitals. The AECOPD risk stratification tool identified three factors with the highest discrimination of mortality risk: BUN >25 mg/dl, Altered mental status, and Pulse >109 per minute (BAP). Based on the number of risk factors present on admission, the BAP classified patients into four risk categories, ranging from Low (0 risk factors) to High (3 factors). We examined mortality, length of stay (LOS), and cost outcomes using the BAP classification algorithm. The cost outcome was calculated using the Centers for Medicare and Medicaid Services (CMS) cost/charge ratio for each hospital for a given calendar year. RESULTS: Overall, median age was 72 (IQR: 63-79) and 55% were women. Crude mortality was 2.4%. The prevalence for each of the BAP risk categories was 51.6% (low), 39.7% (Intermediate I), 7.9% (Intermediate II), and 0.8% (High). The corresponding mortality was 1.0%, 2.7%, 8.2%, 17.6%; the mean LOS was 4.7, 5.4, 6.6, 6.8 days; the mean cost were $5,700, $6,900, $9,400, $11,400 respectively. The trend-analyses revealed a graded association between number of BAP risk factors and worsening outcomes. For every addition of BAP risk factors, there was an exponential increase in mortality risk (OR: 2.89, CI: 2.70-3.09), 0.81 day increase of LOS (CI: 0.76-0.87), and $1600 increase of cost (CI: $1500-$1700). P-values for all trends were <0.0001. CONCLUSIONS: The BAP classification tool accurately differentiates mortality risk. It may also be used to identify high risk cohorts for prolonged LOS and excess cost among hospitalized AECOPD patients.