Reliability and validity of the Japanese translation of the DN4 Diagnostic Questionnaire in patients with neuropathic pain.

Background: The Douleur Neuropathique 4 questionnaire (DN4) is a simple and objective tool developed by the French Neuropathic Pain Group to screen for neuropathic pain.

Methods: This prospective observational study was undertaken in three hospitals to assess the validity of a Japanese translation of the DN4. We first translated the DN4 into Japanese using a forward-backward method. Pain specialists then examined patients independently and diagnosed them with neuropathic or non-neuropathic pain, according to the International Association for the Study of Pain definitions. The Japanese version of the DN4 questionnaire was then given to each patient.

Results: Of 187 patients that met our inclusion criteria, 100 and 87 were diagnosed with neuropathic and non-neuropathic pain, respectively. The test-retest intra-class correlation coefficient (95% confidence interval) was 0.827 (0.769-0.870). Among patients with identical diagnoses of neuropathic or non-neuropathic pain, receiver-operating characteristic curve analysis revealed an area under the curve of 0.89. A cut-off point of equal or greater than 4 resulted in a sensitivity of 71% and specificity of 92%.

Conclusion: The Japanese version of the DN4 was found to be a helpful tool for discriminating between neuropathic and non-neuropathic pain.