Methods
Design
This prospective randomised controlled trial was conducted
during the period from June 2009–March 2011 at the HD
units of two hospitals in Tianjin, China. Eligible subjects
were individually randomised to experimental group andcontrol group using random number table. The sequence
was concealed from all investigators with opaque sealed
envelopes, and these envelopes were given to a nurse who
was not involved in the research. All subjects included in
our study underwent HD three times weekly. We readjusted
the HD treatment time of all participants after allocation,
such that the experimental group received HD
treatment on Monday, Wednesday and Friday and the
control group received HD treatment on Tuesday, Thursday
and Saturday to avoid potential contamination
between groups. Subjects and examiners had no knowledge
of the group assignment. During the period of experiment,
a nephrology nurse collecting and assessing data
was blinded to the random procedure, and she did not
involve in the care of patients.