To ensure that the rights of human subjects were protected,
the research proposal was approved by the Institutional
Review Board at each hospital. Prior to data collection, the
primary investigator explained the purposes and procedures
for this study and written informed consent was obtained
from patients. Potential subjects were told that participation
was voluntary and that declining to participate would not
negatively affect their present or future medical care. Ethical
principles and standards of human rights protection were
adhered to during the entire research process.