Risk Factors for Persistent Problems Following Whiplash Injury: Results of a Systematic Review and Meta-analysis

DM Walton, J Pretty, JC MacDermid, RW Teasell

STUDY DESIGN: Systematic review and meta-analysis. BACKGROUND: Whiplash-associated disorder (WAD) is the most common reported injury following motor vehicle accident. Evidence for prognosis and intervention are difficult to interpret due to differences in inception times, outcomes used, and sample heterogeneity. METHODS: An extensive literature search was conducted to identify published studies of prognosis following whiplash. Rigorous inclusion criteria were applied to allow for meaningful results to be drawn. Data were extracted, transformed where necessary, and pooled to allow estimation of the odds ratio for any factor with at least 3 data points in the literature.

RESULTS: From 11 cohorts (n = 3193), 25 factors were identified with at least 3 data points in the existing literature. Of these, 9 were found to be significant predictors based on the odds ratio and confidence limits: no postsecondary education, female gender, history of previous neck pain,baseline neck pain intensity greater than 55/100, presence of neck pain at baseline, presence of headache at baseline, catastrophizing, WAD grade 2 or 3, and no seat belt in use at time of collision. Neck pain intensity, WAD grade, headache, and no postsecondary education were robust to publication bias.

CONCLUSIONS: Using a rigorous process for the identification and extraction of data from a homogenous subset of the prognostic WAD literature, we were able to identify several factors for which information is easy to collect clinically and could provide clinicians with a good sense of prognosis following whiplash injury. LEVEL OF EVIDENCE: Prognosis, level 1a.

J Orthop Sports Phys Ther 2009;39(5):334-350, Epub 18 July 2008. View Full Article

doi:10.2519/jospt.2009.2765

Filed under: Cervical, Prognosis, Whiplash Injuries , Cervical spine, neck, Prognosis, WAD

Measurement Properties of the Neck Disability Index: A Systematic Review

JC MacDermid, DM Walton, S Avery, A Blanchard, E Etruw, C McAlpine, CH Goldsmith

STUDY DESIGN: Systematic review of clinical measurement. OBJECTIVE: To find and synthesize evidence on the psychometric properties and usefulness of the neck disability index (NDI). BACKGROUND: The NDI is the most commonly used outcome measure for neck pain, and a synthesis of knowledge should provide a deeper understanding of its use and limitations. METHODS AND MEASURES: Using a standard search strategy (1966 to September 2008) and 4 databases (Medline, CINAHL, Embase, and PsychInfo), a structured search was conducted and supplemented by web and hand searching. In total, 37 published primary studies, 3 reviews, and 1 in-press paper were analyzed. Pairs of raters conducted data extraction and critical appraisal using structured tools. Ranking of quality and descriptive synthesis were performed.

RESULTS: Horizon estimation suggested the potential for 1 missed paper. The agreement between raters on quality assessments was high(kappa = 0.82). Half of the studies reached a quality level greater than 70%. Failures to report clear psychometric objectives/hypotheses or to rationalize the sample size were the most common design flaws. Studies often focused on less clinically applicable properties, like construct validity or group reliability, than transferable data, like known group differences or absolute reliability (standard error of measurement [SEM] or minimum detectable change [MDC]). Most studies suggest that the NDI has acceptable reliability, although intraclass correlation coefficients (ICCs) range from 0.50 to 0.98. Longer test intervals and the definition of stable can influence reliability estimates. A number of high-quality published (Korean, Dutch, Spanish, French, Brazilian Portuguese) and commercially supported translations are available. The NDI is considered a 1-dimensional measure that can be interpreted as an interval scale. Some studies question these assumptions. The MDC is around 5/50 for uncomplicated neck pain and up to 10/50 for cervical radiculopathy. The reported clinically important difference (CID) is inconsistent across different studies ranging from 5/50 to 19/50. The NDI is strongly correlated (>0.70) to a number of similar indices and moderately related to both physical and mental aspects of general health.

CONCLUSION: The NDI has sufficient support and usefulness to retain its current status as the most commonly used self-report measure for neck pain. More studies of CID in different clinical populations and the relationship to subjective/work/function categories are required.

J Orthop Sports Phys Ther 2009;39(5):400-417.- full text PDF

doi:10.2519/jospt.2009.2930

Filed under: Cervical, Outcome measure , Cervical spine, Outcome measure, reliability