Author Contributions: Dr Latshang had full access to all of the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis.
Study concept and design: Nussbaumer-Ochsner, Kohler, Bloch.
Acquisition of data: Latshang, Nussbaumer-Ochsner, Henn, Ulrich, Bloch.
Analysis and interpretation of data: Latshang, Henn, Lo Cascio, Ledergerber, Kohler, Bloch.
Drafting of the manuscript: Latshang, Bloch.
Critical revision of the manuscript for important intellectual content: Latshang, Nussbaumer-Ochsner, Henn, Ulrich, Lo Cascio, Ledergerber, Kohler, Bloch.
Statistical analysis: Latshang, Lo Cascio, Ledergerber, Bloch.
Obtained funding: Kohler, Bloch.
Administrative, technical, or material support: Latshang, Nussbaumer-Ochsner, Henn, Ulrich, Lo Cascio, Bloch.
Study supervision: Latshang, Bloch.
Conflict of Interest Disclosures: All authors have completed and submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest. Dr Bloch reported having received unconditional institutional grants from Philips Respironics and ResMed and served as a consultant for imtmedical. No other disclosures were reported.
Funding/Support: This study was supported by grants from the Swiss National Science Foundation, Lung Leagues of Zurich and Schaffhausen, Center for Clinical Research, University of Zurich, and University Hospital Zurich and by an unconditional grant from Philips Respironics, Switzerland.
Role of the Sponsor: The funding sources had no role in the design and conduct of the study; in the collection, analysis, and interpretation of the data; or in the preparation, review, or approval of the manuscript.
Previous Presentation: Parts of this study were presented as abstracts at the annual meeting of the European Respiratory Society; September 18-22, 2010; Barcelona, Spain; and of the American Thoracic Society; May 13-18, 2011; Denver, Colorado.