Reliability, validity and sensitivity to change of neurogenic bowel dysfunction score in patients with spinal cord injury

Abstract

Study design: Psychometrics study. Objectives: The aim of this study is to investigate the validity, reliability and sensitivity to change of neurogenic bowel dysfunction (NBD) score. Setting: Dokuz Eylül University Faculty of Medicine, Turkey. Methods: The study included 42 patients with spinal cord injury (SCI). The reliability of NBD score was assessed by test–retest reliability and internal consistency. Cronbach’s alpha coefficient was calculated to determine internal consistency. The construct validity was evaluated by exploring correlations between the NBD score and SF-36 scales, patient assessment of impact of NBD on quality of life (QoL) and the physician global assessment (PGA). The Global Rating of Change (GRC) scale was used to assess the change of NBD to investigate the sensitivity of the score to change. Results: Cronbach’s alpha coefficient was 0.547. In test–retest reliability analysis, high correlations between total test–retest NBD score and answers of each question were found (r = 1.000, P<0.001). NBD score had a strong and significant correlation with PGA (r = 0.98, P<0.000) and the impact on QoL (r = 0.92, P<0.001). There was a significant negative correlation between NBD score and subscales of SF-36 (P<0.05) except physical functioning, physical role functioning and physical component summary score. There was a significant improvement in NBD scores after treatment (P = 0.011). A significant positive correlation was found between GRC scale and change in total NBD score (r = 0.821, P = 0.007). Conclusion: The Turkish version of the NBD score is a valid and reliable instrument and also sensitive to change in patients with SCI.