Derivation of a clinical prediction rule to identify both chronic moderate/severe disability and full recovery following whiplash injury

Carrie Ritchie, Joan Hendrikz, Justin Kenardy, Michele Sterling

Recovery following a whiplash injury is varied: approximately 50% of individuals fully recover, 25% develop persistent moderate/severe pain and disability, and 25% experience milder levels of disability. Identification of individuals likely to develop moderate/severe disability or to fully recover may help direct therapeutic resources and optimise treatment. A clinical prediction rule (CPR) is a research-generated tool used to predict outcomes such as likelihood of developing moderate/severe disability or experiencing full recovery from whiplash injury. The purpose of this study was to assess the plausibility of developing a CPR. Participants from 2 prospective, longitudinal studies that examined prognostic factors for poor functional recovery following whiplash injury were used to derive this tool. Eight factors, previously identified as predictor variables of poor recovery, were included in the analyses: initial neck disability index (NDI), initial neck pain (visual analogue scale), cold pain threshold, range of neck movement, age, gender, presence of headache, and posttraumatic stress symptoms (Posttraumatic Diagnostic Scale [PDS]). An increased probability of developing chronic moderate/severe disability was predicted in the presence of older age and initially higher levels of NDI and hyperarousal symptoms (PDS) (positive predictive value [PPV]=71%). The probability of full recovery was increased in younger individuals with initially lower levels of neck disability (PPV=71%). This study provides initial evidence for a CPR to predict both chronic moderate/severe disability and full recovery following a whiplash injury. Further research is needed to validate the tool, determine the acceptability of the proposed CPR by practitioners, and assess the impact of inclusion in practice.