PURPOSE:COPD is a common cause of hospitalization and mortality. Physicians face challenges in determining the need for mechanical ventilation (MV) in acute exacerbations of COPD (AECB). We sought to validate a clinical risk score that correlates with hospital mortality in AECBs and to evaluate its utility at predicting the need for MV in AECBs.
METHODS:We reviewed a large, multi-center inpatient database including 191 hospitals in the US and focused on persons admitted in 2004–2006 for AECB. We randomly split the population (n=98,036 COPD admissions) into training and validation cohorts. The original COPD mortality risk stratification tool consists of BUN >25 mg/dl, Altered mental status, and Pulse >109 per minute. Based on number of risk factors present, the algorithm classifies patients into 4 risk categories, ranging from Low (0 risk factors) to High (3 factors). We examined the prevalence of MV on admission using this classification algorithm for the training cohort. We then validated the score in the remaining population. We used the area under receiver operating curves (ROCs) to assess the score’s discrimination.
RESULTS:The overall crude mortality was 2.2%. The median age was 72 (IQR: 63–79) and 55% of patients were women. For patients with 0, 1, 2, or 3 risk factors, the respective mortality rates were: 1.1%, 2.4%, 7.0%, 18.0% for the derivation cohort and 1.0%, 2.6%, 7.6%, 14.9% for the validation cohort. The corresponding MV rates on admission were 0.4%, 1.4%, 6.2%, 11.4% for the derivation cohort and 0.3%, 1.3%, 6.5%, 14.2% for the validation cohort. The area under ROC was 0.76 for predicting the need for MV on admission in the training cohort vs. 0.77 in the validation cohort (p=NS).
CONCLUSION:Three common variables easily assessed at time of presentation differentiate risks for both mortality and the need for MV in persons with AECBs.
CLINICAL IMPLICATIONS:Broad use of a validated risk stratification score in AECB can facilitate triage and foster rapid identification of persons at high risk for respiratory failure from COPD.
DISCLOSURE:Andrew Shorr, No Financial Disclosure Information; No Product/Research Disclosure Information