Medline ® Abstract for Reference 18
of 'Prevention and management of side effects in patients receiving opioids for chronic pain'
Validation of the Bowel Function Index to detect clinically meaningful changes in opioid-induced constipation.
Rentz AM, Yu R, Müller-Lissner S, Leyendecker P
J Med Econ. 2009;12(4):371-83.
OBJECTIVE: The Bowel Function Index (BFI) is a clinician-administered, patient-reported, 3-item questionnaire to evaluate opioid-induced constipation in cancer and non-cancer chronic pain patients. The objective of the present analysis was to evaluate the psychometric characteristics of the BFI using data from clinical studies of oral prolonged release (PR) oxycodone/naloxone.
METHODS: OXN2401 was a multicenter, controlled, randomized, double-blind, parallel-group study including oral PR oxycodone combined with oral PR naloxone as well as oral PR oxycodone combined with corresponding naloxone placebo. OXN3401 and OXN3001 were 12-week multicenter, controlled, randomized, double-blind, parallel-group studies of a fixed combination of oral PR oxycodone/naloxone versus PR oxycodone. In addition, a placebo group was included in study OXN3401. BFI psychometric characteristics (reliability, reproducibility, convergent/known groups validity, and responsiveness) were evaluated.
RESULTS: Demographic data (n=985) were comparable and analyses indicated a high degree of internal consistency (Cronbach's alpha>0.7). Change of less than 5 points in BFI was indicative of high reproducibility. Correlations between BFI item and total scores to stool frequency were statistically significant and in the low-to-moderate range (OXN2401 -0.23 to -0.29, p<0.001; OXN3401 range -0.26 to -0.40, p<0.001; OXN3001 -0.14 to -0.15, p<0.05). Data indicate that a BFI score change of≥12 points represents a clinically meaningful change in constipation.
LIMITATIONS: This publication for validation of BFI only includes data from three clinical trials. However, another publication of an additional specifically designed cross-sectional validation study is in preparation.
CONCLUSION: The BFI is a valid and reliable instrument for the assessment of opioid-induced constipation in chronic pain patients. Psychometric analyses from clinical trials support the BFI's psychometric properties.
Center for Health Outcomes Research, United Biosource Corporation, Bethesda, MD, USA.