The diagnostic accuracy and test-retest reliability of the Dutch PainDETECT and the DN4 screening tools for neuropathic pain in patients with suspected cervical or lumbar radiculopathy

BACKGROUND: It is important to identify neuropathic pain early to guide treatment decisions and prevent chronicity. There is lack of evidence whether the Dutch painDETECT questionnaire and Douleure Neuropathique en 4 questions (DN4) can adequately assess neuropathic pain.

METHODS: Patients suspected of cervical or lumbar radiculopathy were eligible for inclusion. The Dutch painDETECT and DN4 were considered as the index tests and were compared to the reference test consisting of the consensus expert diagnosis by using the grading system for neuropathic pain. The index tests and neuropathic pain diagnosis were blindly performed. Diagnostic accuracy was determined by calculating sensitivity, specificity, predictive values and likely hood ratios. Test-retest reliability for the index tests was assessed using Intraclass Correlation Coefficients (ICC).

RESULTS: A total of 180 patients were included, of which 110 for the reliability analysis. Fifty-nine patients (33%) had neuropathic pain according to the reference test. Both the painDETECT and DN4 had moderate sensitivity of respectively 75% (95% CI: 61.6-85.0) and 76% (95% CI: 63.4-86.4) and poor specificity of respectively 51% (95% CI: 42.0-60.4) and 42% (95% CI: 33.2-51.5). Combining negative test results for both screening tools increased the sensitivity up to 83% (95% CI: 71.0-91.6). The ICC for the painDETECT was 0.91 (95% CI: 0.86-0.94) and for the DN4 0.86 (95% CI: 0.80-0.91).

CONCLUSIONS: The use of the Dutch painDETECT and the DN4 in patients with suspected radiculopathy should not be recommended yet. A combination of both screening tools seems most suitable to rule out neuropathic pain in patients suspected of radiculopathy.

LEVEL OF EVIDENCE: Diagnosis, Level 1B.