Implication of the Nociplastic Features for Clinical Diagnosis of Fibromyalgia: Development of the Preliminary Nociplastic‐Based Fibromyalgia Features (NFF) Tool

OBJECTIVE: Nociplastic concept incorporates a broad continuum of pain phenotypes shared with clinical peculiarity. This study aimed to develop and validate a diagnostic tool, the preliminary Nociplastic‐based Fibromyalgia Features (NFF), to detect fibromyalgia (FM) in patients with chronic pain. METHODS: Items requiring yes or no responses and relating to the most relevant clinical nociplastic pain (NP) features of FM were compiled by a group of expert rheumatologists. The provisional list was tested in a prospective study on 185 consecutive patients with chronic pain (126 patients with FM and 59 patients with non‐FM non‐inflammatory chronic pain) diagnosed based on expert decision. Identification of the most discriminant combinations of items for FM and the calculation of their sensitivity and specificity were based on both univariate and multivariate (stepwise logistic regression) analyses. All participants were investigated through the final NFF, the 2011 American College of Rheumatology (ACR) criteria, and the 2016 ACR criteria. NFF performance was assessed with receiver operating characteristic curve analysis. RESULTS: Based on multivariate analyses, we retained only seven items in the final version of the NFF. A cut‐off score of 4 (corresponding to the number of positive items) gave the highest rate of correct identification of patients (85%), with a sensitivity of 82% and a specificity of 91%. The NFF showed the highest concordance rate with expert diagnosis (85%) and the lowest value (77%) with the ACR 2016 criteria. CONCLUSION: The preliminary NFF with respect to the various aspects of NP showed good performance for detection of the FM in the clinical setting. This tool may provide a more pragmatic approach to the timely diagnosis of FM.