Prevalence of neuropathic pain according to the IASP grading system in patients with chronic non-malignant pain.

OBJECTIVE The primary objective was to determine the prevalence of neuropathic pain according to the new International Association for the Study of Pain (IASP) grading system. The secondary objective was to compare the system classification of neuropathic pain with the classification of neuropathic pain according to a patient-administered screening questionnaire. SETTING A Multidisciplinary Pain Center. SUBJECTS One hundred twenty patients with a variety of chronic pain conditions referred to a multidisciplinary pain center. METHODS Consecutively referred patients filled out the PainDETECT Questionnaire before the first consultation. During the first consultation, patients had pain history taken and bedside examination performed by a pain specialist. Patients were classified according to the score on the PainDETECT Questionnaire and graded according to the IASP grading system about the certainty of neuropathic pain. RESULTS According to the IASP grading system, 22 patients (18.3%) classified as probable or definite neuropathic pain and 90 patients (75%) as unlikely neuropathic pain. According to the PainDETECT Questionnaire, 55 patients (45%) were classified as likely neuropathic pain and 13 patients (10.8%) as unlikely neuropathic pain. Eleven patients (20%) who were classified as neuropathic pain according to PainDETECT were also classified as probable or definite neuropathic pain by the new IASP grading system. CONCLUSIONS According to the new IASP grading system, less than 20% of the patients referred to a multidisciplinary pain center fulfilled the criteria for neuropathic pain. The classification of neuropathic pain with the IASP system varies from the classification of neuropathic pain with the use of a self-administered screening questionnaire.