Utility of the Oswestry Disability Index for studies of back pain related disability in nurses: Evaluation of psychometric and measurement properties

Background: Disability due to back pain in nurses results in reduced productivity, work absenteeism and attrition from the nursing workforce internationally. Consistent use of outcome measures is needed in intervention studies to enable meta-analyses that determine efficacy of back pain preventive programs. Objective: This study investigated the psychometric and measurement properties of the Oswestry Disability Index (ODI) in nursing students to determine its suitability for assessing back pain related disability in intervention studies. Methods: Bachelor of Nursing students were recruited. Test-retest reliability and the ability of the ODI to discriminate between individuals with serious and non-serious back pain were investigated. The measurement error of the ODI was examined with the minimal detectable change at the 90% confidence level (MDC(90)). Results: Student nurses (n = 214) had a low mean ODI score of 8.8 +/- 7.4%. Participants with serious back pain recorded higher scores than the rest of the cohort (p < 0.05). Test-retest reliability examined in 33 individuals was ICC = 0.88 (95%CI 0.77-0.94). The MDC(90) = 6%, and 36% of nursing students scored below the MDC(90) indicating the tool had limited ability to detect longitudinal change in disability in this population. Conclusion: Data from this and previous studies demonstrate that the measurement properties of the ODI are inappropriate for studying back pain related disability in nurses. The ODI is not recommended for back pain intervention studies in the nursing population and an alternative tool that is sensitive to lower levels of disability must be determined. (C) 2009 Elsevier Ltd. All rights reserved.