Reliability of the questionnaire was tested through test and
retest in phase four (August–October 2012). In the test stage 48/
70 (68.6%) potential participants returned questionnaires; in the
retest 41/48 questionnaires were returned (one participant died
and 6 did not respond to the second mailing). Five participants
were excluded as they changed from remission to active disease
or vice versa on the HBI or SCCAI between the test and retest.
This left 36 patients for inclusion in the analysis. The aim of the
analysis was to assess the repeatability of the IBD-F scale and to
compare this with equivalent values for the MFI and MAF.
Agreement between the test and retest questionnaires
was also examined for individual items of the IBD-F. For the
purposes of analyses, individual items were considered to be
continuous in nature. Agreement between the test and
retest measurements is shown in Table 2. There were few
missing items and most questions with less than 36 responses
were those with a N/A option.