The bowel function instrument for rectal cancer survivors with anastomosis and ostomy

Abstract

ObjectiveRectal cancer is often treated with surgery such as ostomy or anastomosis. The Bowel Function Instrument (BFI) is a valid and reliable 18-item measure of physical bowel symptoms. Some items on the BFI do not apply to those with ostomies. We reanalyzed data from a previous validation study to inform the best method for scoring the BFI for both people with ostomies and anastomosis. MethodsPeople (n = 575) with rectal cancer treated with ostomy (n = 181, 31 %) or anastomosis (n = 394, 69 %) completed the BFI and Short Form 12 (SF12) measure on a mailed survey. The full BFI has three subscales and a total score based on 14 items: soilage/urgency (4 items); frequency of bowel movements (6 items); and dietary changes (4 items). We used confirmatory factor analysis (CFA) to examine two versions (8-item, 11-item) of the BFI adapted for use with both ostomy and anastomosis. We also examined reliability and validity of the version supported by the CFA. ResultsCFA results supported the 8-item BFI that included only the soilage/urgency items and dietary changes items but not the frequency items. The 8-item BFI was reliable (Cronbach's alpha of 0.788). The 8-item BFI score significantly correlated with all SF12 subscales with Pearson correlations ranging from 0.115 (Vitality) to 0.318 (social function). ConclusionsThe 8-item version of the BFI was valid and reliable as a total score for people with ostomy or anastomosis. The 8-item BFI may be useful for monitoring bowel function during and after treatment for rectal cancer.