Validation of the Bowel Function Index to detect clinically meaningful changes in opioid-induced constipation.
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.


CONCLUSIONS
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.


CONCLUSIONS
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.
Rentz
A M
AM
Center for Health Outcomes Research, United Biosource Corporation, Bethesda, MD, USA.
Yu
R
R
Müller-Lissner
S
S
Leyendecker
P
P
D000701:Analgesics, Opioid / Q000008:administration & dosage / Q000009:adverse effects*; D002908:Chronic Disease; D003248:Constipation / Q000139:chemically induced* / Q000175:diagnosis* / Q000188:drug therapy / Q000503:physiopathology; D003692:Delayed-Action Preparations; D059026:Diagnostic Self Evaluation; D004311:Double-Blind Method; D004359:Drug Therapy, Combination; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009270:Naloxone / Q000008:administration & dosage; D009292:Narcotic Antagonists / Q000008:administration & dosage; D010098:Oxycodone / Q000008:administration & dosage / Q000009:adverse effects*; D010146:Pain / Q000188:drug therapy; D015203:Reproducibility of Results; D012720:Severity of Illness Index; D011795:Surveys and Questionnaires
D000701:Analgesics, Opioid; D003692:Delayed-Action Preparations; D009292:Narcotic Antagonists; D009270:Naloxone; D010098:Oxycodone