Objective: To develop a patient-completed screening tool to help differentiate nociceptive and neuropathic pain.
Research design and methods: A multicenter study was performed for item reduction (initial 89-item questionnaire) and model building. Patients (N = 586) with non-headache chronic pain completed the questionnaire and were referred to pain specialists for diagnosis. Factor and regression analyses were used to derive a final, 6-item questionnaire – ID Pain. A second multicenter study evaluated reliability and validity. Patients (N = 308) treated by pain specialists completed ID Pain and validation measures.
Main outcome measures: Sensitivity and specificity were assessed using receiver operating characteristic curves and the concordance c index. Reliability was assessed using a κ statistic and intraclass correlation coefficient.
Results: Final 6 items were: did the pain feel: (1) like pins and needles? (2) hot/burning? (3) numb? (4) like electrical shocks? (5) is the pain made worse with the touch of clothing or bed sheets? (6) is the pain limited to your joints? ‘Yes’ answers to questions 1–5 were scored as 1, while a ‘yes’ answer to question 6 was scored as –1. ‘No’ answers were scored as 0. Higher scores (–1 to 5) suggested a neuropathic component. The questionnaire accurately predicted diagnoses of neuropathic pain made by pain specialists. The concordance c indices in the studies were 0.73 and 0.69. The ICC was 0.742; the κ statistic ranged from 0.742 to 0.527.
Conclusions: ID Pain appeared to accurately indicate the presence of a neuropathic component of pain. As a brief, self-administered screening tool, it could be useful in primary care settings.
