Low immunoglobulin levels affect the course of COPD in hospitalized patients.

"Declarations Ethics approval and consent to participateThe study was approved by the University of Alberta health research ethics review board (approval number Pro00038838). Informed consent was obtained from all participants involved in the study. Consent for publicationNot applicable. Competing interestsThe authors declare that they have no competing interests in this section. Competing interests The authors declare that they have no competing interests in this section."

"Funding Funding for this study was provided by an Investigator initiated grant from CSL Behring Recruitment of patients and collection of clinical data were supported by an Alberta Innovates Health Solutions grant (#201200821) to Dr. Michael K. Stickland. Dr. Rowe’s research is supported by a Scientific Director’s Grant (SOP 168483) from the Canadian Institutes of Health Research (CIHR) through the Government of Canada (Ottawa, ON). These funding organizations were not involved in any aspect of the conduct, analysis, and manuscript preparation of this study. The funders assume no responsibility for the conduct of the research, nor the results reported."

"Trial registration statement : Retrospectively registered."