Neuropathic pain: A patient‐centred approach to measuring outcomes

BACKGROUND: Neuropathic pain (NP) is a complex, chronic pain state initiated by a primary lesion or dysfunction of the nervous system and presents as a variety of symptoms across multiple disease states. OBJECTIVE: To develop a patient‐centred conceptual model of symptoms and impacts in subjects with diabetic peripheral neuropathy (DPN) or post‐herpetic neuralgia (PHN) that can inform the measurement strategy in clinical trials. METHOD: Thirty subjects with DPN or PHN participated in in‐person interviews which were performed until saturation was achieved. Transcripts were analysed in ATLAS.ti. RESULTS: Interviews were completed with DPN subjects (United States, n = 10; Japan, n = 10) and PHN subjects (United States, n = 5; Japan, n = 5). Numbness and tingling were frequently reported symptoms in the DPN population while itchiness and hypersensitivity were predominant in PHN. Both populations experienced burning and ache/soreness with similar frequency. DPN subjects experienced pain primarily in their lower extremity (eg feet, ankles), while PHN subjects experienced pain primarily in the chest and back. Impacts reported by DPN subjects included difficulty walking, sleep disturbance and climbing stairs. Impacts in PHN subjects included sleep disturbance, avoidance of physical contact, being angry/frustrated and being sad/depressed. Overall, concepts in Japan were not qualitatively different from the United States. Conceptual models of NP were generated based on the concepts elicited. CONCLUSIONS: This research highlights core concepts to measure from the patient's perspective. Moreover, it enables the assessment of existing measures, the possible modification of these measures, or if a new NP measure with improved sensitivity and responsiveness is merited.