Psychometric and accuracy comparison of three commonly used questionnaires for the diagnosis of neuropathic pain

Objectives: Diagnosis of neuropathic pain is challenging. Recently, scientists developed multiple questionnaires to expedite this diagnosis including the Self-completed Leeds Assessment of Neuropathic Symptoms and Signs (S-LANSS), Douleur Neuropathique 4 questionnaire (DN4), and Neuropathic Pain Questionnaire-Short Form (NPQ-SF). Materials and Methods: We conducted a prospective cohort study to compare the psychometric characteristics and accuracy of the three questionnaires. We assessed reliability with the Cronbach's α reliability coefficient and inter-item correlations, and validity with receiver operating characteristic (ROC) and correlation analyses. We assessed agreement between the diagnosis of the questionnaires and the reference clinical diagnosis using Cohen's kappa coefficient. Results: 188 patients were analyzed: 141 (75%) had "definite neuropathic" and 47 (25%) had "nonneuropathic" pain. The NPQ-SF and S-LANSS questionnaires demonstrated acceptable reliability with Cronbach's α coefficient values of 0.54 (95% CI: 0.41-0.64) and 0.65, (95%CI: 0.57-0.72), respectively. The DN4 questionnaire demonstrated high reliability with Cronbach's α coefficient of 0.74 (95%CI: 0.68-0.79). The NPQ-SF, DN4, and S-LANSS questionnaires demonstrated "excellent" diagnostic ability with an area under the ROC curve of 0.82 (95% CI: 0.75-0.89), 0.89 (95% CI: 0.83-0.95), and 0.83 (95% CI: 0.75-0.90), respectively. Based on their optimal cutoff values, the DN4 had the highest sensitivity and lowest specificity in discriminating between neuropathic and nonneuropathic patients, while the S-LANSS had the lowest sensitivity and highest specificity. Conclusion: Both NPQ-SF and S-LANSS demonstrated acceptable reliability, while DN4 demonstrated high reliability. All three demonstrated excellent diagnostic validities; however, it is important to consider the sensitivity and specificity of each.