Physician-assigned Diagnosis Versus Questionnaire-based Measures in Individuals with Nociceptive, Neuropathic, and Nociplastic Pain: A Mechanism-based Characterization of Chronic Pain Patients.

BACKGROUND

The International Association for the Study of Pain (IASP) has defined three mechanisms for chronic pain: nociceptive, neuropathic, and nociplastic. Accurate differentiation between these mechanisms is essential for treatment selection but remains challenging due to symptom overlap and reliance on clinical judgment. Patient-reported questionnaires may support diagnosis, though their diagnostic accuracy relative to physician assessment has not been fully established.

OBJECTIVES

This study aimed to investigate the prevalence and overlap of chronic pain mechanisms in a tertiary pain clinic population and to compare physician-assigned diagnoses with results from patient-reported questionnaires.

METHODS

This cross-sectional study recruited 89 adult patients with chronic pain from the Rambam Institute for Pain Medicine at Rambam Health Care Campus in Haifa, Israel. Each participant underwent a comprehensive physician evaluation based on the criteria of the International Classification of Diseases and Related Health Problems, 11th revision, and completed the Central Sensitization Inventory (CSI), PainDETECT, and 2016 American College of Rheumatology (ACR) Fibromyalgia Diagnostic Criteria surveys. Diagnostic agreement, sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were calculated using physician diagnosis as the reference standard.

RESULTS

Physician diagnoses identified neuropathic pain in 51 patients (57.3%), nociceptive pain in 38 (42.7%), and nociplastic pain in 25 (28.1%), with substantial diagnostic overlap (32.6% with ≥2 mechanisms). The CSI demonstrated high sensitivity (92.0%) but low specificity (45.3%) for nociplastic pain. PainDETECT showed moderate accuracy for neuropathic pain (sensitivity 68.6%, specificity 52.6%) and higher specificity for nociceptive pain (86.3%). The 2016 ACR Fibromyalgia criteria provided a more balanced diagnostic profile (sensitivity 88.0%, specificity 68.8%).

CONCLUSIONS

Questionnaire-based measures are useful for screening chronic pain mechanisms but demonstrate variable accuracy when compared to physician diagnoses, particularly in the context of overlapping pain phenotypes. Refinement of diagnostic thresholds, combined assessment strategies, and updated questionnaires may improve differentiation of pain subtypes and enhance clinical decision-making.