Acute exacerbations of chronic obstructive pulmonary disease (COPD) are a frequent cause of hospitalization in the United States. Previous studies of selected populations of patients with COPD have estimated in-hospital mortality to range from 4% to 30%. Patil and colleagues performed a cross-sectional study utilizing the 1996 Nationwide Inpatient Sample (a data set of all hospitalizations from a 20% sample of nonfederal US hospitals) to obtain generalizable estimates of in-hospital mortality in patients admitted for acute exacerbation of COPD, describe the admission characteristics of these patients, and identify risk factors for in-hospital mortality based on administrative data routinely collected in this population. The study population included 71 130 patients 40 years or older with an acute exacerbation of COPD at hospital discharge. The authors found that in-hospital mortality for patients with an acute exacerbation of COPD was 2.5%, with multivariable analyses identifying older age, male sex, higher income, nonroutine admission sources, and more comorbid conditions as independent risk factors for in-hospital mortality, and conclude that these findings demonstrate that administrative data collected in large patient populations can provide useful information regarding patient outcomes in acute exacerbations of COPD.