Methods
Design: A cross-sectional descriptive design
was used in this study.
Ethical Considerations: Approval for
conducting this study was obtained from the Institutional
Review Board (IRB) of Mahidol University and the
research ethics committee of the hospitals used as the
study sites. The Protocol number is ID 04-55-33.
All participants were informed regarding: the study’s
purpose; assurance of privacy and confidentiality; their
right to withdraw from the study without penalty or
effect on their treatment; and the usefulness of the
study outcome. Those agreeing to participate were
asked to sign a consent form.
Sample and Setting: The sample size
was obtained from the study size for exploratory
factor analysis, which was to include five times
the number of 54 in the assessment form, thus,
the estimated number was approximately 270.
Even though 270 potential participants were
approached, only 250 were willing to participate
in the study. The number of 250 was adequate to
determine symptom cluster and showed a high
Kaiser-Meyer Olkin (KMO=.904) measure of
sampling adequacy.17 Thus, the sample size used
in this study was 250.
The participants, confirmed as having COPD
by a physician, and able to follow up at respiratory
clinics in one university hospital and one provincial
hospital during July 2012 to September 2013. After
reviewing medical records, we decided our purposive
sample was inclusive of those: (1) aged 35 years or
older (since most of COPD start from age 40,23 thus,
we identified the age of 35 as a lowest age which could
be possible for this group); (2) willing to participate;
(3) and able to speak, read and write in Thai. Such
participants were invited into the study by the first
author.