Abstract

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 kappa 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 kappa 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.