Psychometric testing of Ibadan low back pain disability questionnaire

BACKGROUND: The Ibadan Low Back Pain Disability Questionnaire (ILBPDQ) was developed to meet the need for a LBP treatment outcome measure that was appropriate for the Nigerian culture and environment. The objective of this study was to determine the psychometric properties of ILBPDQ. METHODS: This study used the validation design. One hundred and forty-two participants with LBP (LBPPs) and 142 age and sex-matched participants without LBP (NLBPPs) were included. The LBPPs were recruited consecutively from Physiotherapy clinics of selected tertiary hospitals in the six geopolitical zones of Nigeria. Both LBPPs and NLBPPs completed the ILBPDQ - the LBPPs completed the Numerical Pain Rating Scale (NPRS). The ILBPDQ was completed by 113 LBPPs two days after initial assessment. Sixty-four of the LBPPs received physiotherapy for 5-weeks, after which they were reassessed using ILBPDQ and NPRS. RESULTS: ILBPDQ score of LBPPs was significantly higher than that of NLBPPs (construct validity) and LBPPs NPRS score correlated significantly with their ILBPDQ score (r = 0.50) at baseline and post intervention (r =0.35) (divergent validity). ILBPDQ scores at baseline and 48 hours later for LBPPs correlated significantly (Intra Class Correlation =0.80) (test re -test reliability). Cronbach's α for ILBPDQ was 0.84 (internal consistency). The postintervention ILBPDQ and NPRS scores for LBPPs were significantly lower than their pre-intervention ILBPDQ scores (responsiveness) and NPRS scores. The changes in ILBPDQ and NPRS scores of the LBPPs correlated significantly (r =0.62) (responsiveness). CONCLUSION: The ILBPDQ demonstrated evidence of validity, reliability and responsiveness. FUNDING: University of Ibadan Senate Research Grant.