German version of the whiplash disability questionnaire: reproducibility and responsiveness.

Michael McCaskey,Corina Schuster,Thierry Ettlin

doi:10.1186/1477-7525-11-36

Abstract

BackgroundThe Whiplash Disability Questionnaire (WDQ) poses a validated tool for the assessment of patients who experience whiplash-associated disorders. A German translation and cross-cultural adaptation was recently produced and presented high validity and internal consistency. As a follow-up, the presented study tests the translated Whiplash Disability Questionnaire’s (WDQ-G) retest reliability and responsiveness to change.MethodsThe WDQ-G was assessed on three different measurement events: first upon entry (ME1), second four days after entry (ME2), and third at discharge (ME3). Test-retest reliability data from ME1 and ME2 was analysed in a group of stable patients to obtain the intraclass correlation coefficient (ICC) and the standard error of measurement (SEM). To test the instrument’s responsiveness, WDQ-G change data were compared to concurrent instruments. The probability of each instrument, to correctly distinguish patients of the stable phase (ME1 to ME2) from patients who deemed to have improved between from ME1 to ME3, was analysed.ResultsIn total, 53 patients (35 females, age = 45 ± 12.2) were recruited. WDQ-G scores changed from ME1 to ME2 by 5.41 ± 11.6 points in a stable group. This corresponds to a test-retest reliability of ICC = 0.91 (95% CI = 0.80–0.95) with a SEM of 6.14 points. Minimal Detectable Change, at 95% confidence, was calculated to be 17 points change in scores. Area under Receiver Operator Characteristics of the WDQ-G’s responsiveness revealed a probability of 84.6% (95% CI = 76.2%–93%) to correctly distinguish between improved and stable patients. Optimal sensitivity (73.2%) and specificity (76.2%) was established at 11-point change.ConclusionsHigh retest reliability and good responsiveness of the WDQ-G support clinical implementation of the translated version. The data suggest, that change in total score greater than eleven points can be interpreted as clinical relevant from a patient’s perspective. Minimal Important Change is suggested at 15 points where there is still high specificity and a 90% confidence MDC.

Highlights

The Whiplash Disability Questionnaire (WDQ) poses a validated tool for the assessment of patients who experience whiplash-associated disorders
But 17 patients failed to return complete data sets leaving a dataset of 53 patients for analysis (35 females, mean age 45 ± 12.2) referred to as non-dichotomised group
On the self-reported questionnaire, 10 patients (18%) indicated to have had Mild traumatic brain injury (MTBI) from the accident and 7 patients reported still being involved in litigation

Summary

Introduction

The Whiplash Disability Questionnaire (WDQ) poses a validated tool for the assessment of patients who experience whiplash-associated disorders. In the past two decades there have been two noteworthy projects attempting to produce recommendations concerning handling cases of WAD: the Quebec Task Force (QTF) on WAD [3] and, as part of the Bone and Joint Decade 2000–2010, the Task Force on Neck Pain and Its Associated Disorders [2] Both publications contributed vastly to the understanding of the complex nature of whiplash and the classification of subgroups in patients allowing a more specific therapy. The WDQ is a self-administered outcome measure to evaluate pain intensity and limitations due to a WAD in different domains: current pain level, personal care, role performance, mobility, sleep disturbances, tiredness, social and leisure (sporting and non-sporting) activity, emotional and cognitive impairments It is a self-administered disease-specific questionnaire consisting of 13 items to which the patients respond by circling their personal agreement on an 11point scale (zero to ten) for each item. Its psychometric qualities have been evaluated and it has been approved to be a valid tool to describe and monitor the perceived participation in everyday activity of patients with WAD [7,8]

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