Rationale: The patterns and outcomes of noninvasive, positivepressure ventilation (NIPPV) use in patients hospitalized for acute exacerbations of chronic obstructive pulmonary disease (COPD) nationwide are unknown. Objectives: To determine the prevalence and trends of noninvasive ventilation for acute COPD. Methods: We used data from the Healthcare Cost and Utilization Project's Nationwide Inpatient Sample to assess the pattern and outcomes of NIPPV use for acute exacerbations of COPD from 1998 to 2008. Measurements and Main Results: An estimated 7,511,267 admissions for acute exacerbations occurred from 1998 to 2008. There was a 462% increase in NIPPV use (from 1.0 to 4.5% of all admissions) and a 42% decline in invasive mechanical ventilation (IMV) use (from 6.0 to 3.5% of all admissions) during these years. This was accompanied by an increase in the size of a small cohort of patients requiring transition from NIPPV to IMV. In-hospital mortality in this group appeared to be worsening over time. By 2008, these patients had a high mortality rate (29.3%), which represented 61% higher odds of death compared with patients directly placed on IMV (95% confidence interval, 24-109%) and 677% greater odds of death compared with patients treated with NIPPV alone (95% confidence interval, 475-948%). With the exception of patients transitioned from NIPPV to IMV, in-hospital outcomes were favorable and improved steadily year by year. Conclusions: The use of NIPPV has increased significantly over time among patients hospitalized for acute exacerbations of COPD, whereas the need for intubation and in-hospital mortality has declined. However, the rising mortality rate in a small but expanding group of patients requiring invasive mechanical ventilation after treatment with noninvasive ventilation needs further investigation.Keywords: COPD; positive-pressure ventilation; artificial respiration; epidemiology Chronic obstructive pulmonary disease (COPD) is the fourth leading cause of death in the United States and is projected to become the third leading cause of death by 2020 (1, 2). A large proportion of morbidity and mortality from COPD results from acute exacerbations, which lead to 1.5 million emergency room visits and 750,000 hospitalizations annually in the United States (3, 4). Therefore, to improve outcomes and reduce mortality due to COPD, we need to optimize the management of acute exacerbations (5), including the correct use of respiratory support modalities to treat patients with respiratory failure.Over the last decade, noninvasive, positive-pressure ventilation (NIPPV) has started playing an increasingly important role in the treatment of respiratory failure due to acute exacerbations (6-12). This is because clinical trials demonstrate good efficacy for NIPPV in reducing risk of intubation and mortality, health care providers are becoming increasingly confident with its use, and unlike IMV, it can be implemented outside the ICU, freeing up ICU beds. Therefore, it appears likely that NIPPV use will continue to increa...