title: Evaluation of the accuracy of several symptoms and domains in distinguishing patients diagnosed with fibromyalgia from healthy controls.
abstract: OBJECTIVE
  To assess the discriminative power of several symptoms and domains that may assist in the diagnosis of subjects with Fibromyalgia (FM).
  
  
  METHODS
  79 individuals with FM and 66 healthy controls participated in the study. The potential domains proposed by the American College of Rheumatology (ACR) criteria were considered (Wolfe et al., 1990). Binary logistic regression and area under a ROC curve (AUC) were used to rank the importance of the variables in distinguishing patients from pain-free controls. Z values were then calculated to compare the AUC values obtained for each variable with that which yielded the highest AUC (reference standard). For each measure, the cut-offs that maximise sensitivity and specificity were also calculated.
  
  
  RESULTS
  The mean pressure pain threshold (PPT) yielded the highest discriminative power (AUC, 0.991) and was therefore chosen as the reference standard; considering an optimal cut- off ≤3.97, it correctly classified 95% of patients and 97% of controls. The discriminative powers of tender point count (cut-off ≥9), health-related quality of life (cut-off ≤63.27) and vitality (cut-off ≤46.97) were as good as that of the reference standard. Finally, items related to physical role and function, body pain, fatigue and memory loss showed adequate discriminative power, although slightly lower than that of the reference.
  
  
  CONCLUSIONS
  In addition to pain, health-related quality of life and fatigue/vitality were confirmed as the best predictors of individuals with FM. The study findings indicate that tender point count and especially pressure pain threshold (measured with an algometer) continue to be key issues in the clinical assessment of subjects with FM relative to pain-free controls.
authors.affiliation: Research Foundation of La Fe Hospital, Valencia, Spain.
authors.forename: Claudio
authors.initials: C
authors.lastname: Gómez-Perretta
authors.affiliation: Department of Clinical Psychology and Psychobiology, University of Santiago de Compostela, Spain.
authors.forename: Yolanda
authors.initials: Y
authors.lastname: Triñanes
authors.affiliation: Department of Clinical Psychology and Psychobiology, University of Santiago de Compostela, Spain.
authors.forename: Alberto J
authors.initials: AJ
authors.lastname: González-Villar
authors.affiliation: Department of Clinical Psychology and Psychobiology, University of Santiago de Compostela, Spain. mteresa.carrillo@usc.es.
authors.forename: Maria T
authors.initials: MT
authors.lastname: Carrillo-de-la-Peña
mesh_terms: D000328:Adult; D019540:Area Under Curve; D061827:Dimensional Measurement Accuracy; D005221:Fatigue / Q000175:diagnosis / Q000209:etiology; D005260:Female; D005356:Fibromyalgia / Q000175:diagnosis / Q000453:epidemiology / Q000503:physiopathology / Q000523:psychology; D006801:Humans; D008297:Male; D008875:Middle Aged; D010147:Pain Measurement / Q000379:methods; D017288:Pain Threshold / Q000502:physiology / Q000523:psychology; D011788:Quality of Life; D012720:Severity of Illness Index; D013030:Spain / Q000453:epidemiology; D063189:Symptom Assessment / Q000379:methods / Q000592:standards