Background Fibromyalgia (FM) requires an expert clinical examination that constitutes a limitation for an easy assessment of diagnostic criteria of the American College Rheumatology (ACR) 1990 in some health settings. This problem leads to delays of diagnosis, treatment, and referral to specialized services. To solve this problem, a new screening criteria, the ACR Preliminary Diagnostic Criteria for FM, was created.
Objectives The aim of this study is to investigate the reliability and validity of the Spanish version of the 2010 ACR Preliminary Diagnostic Criteria for FM.
Methods The Spanish translation of the original 2010 ACR classification questionnaire was carried out by consensus of Rheumatologists from the FM Study Group of the Spanish Society of Rheumatology. We conducted a prospective and multicenter study, including a total of 1169 patients who were divided into 3 groups. Group of study: 813 FM patients diagnosed by a rheumatologist according to the 1990 ACR criteria. Control groups: 147 Rheumatoid Arthritis (RA) patients and 219 Osteoarthritis (OA) patients. They all gave their informed consent and the study was approved by the local Ethical Committee. We evaluated the number of tender points at the time of the study, the Widespread Pain Index (WPI), Symptom Severity Scale (SS1 and SS2), and the Fibromyalgia Impact Questionnaire (FIQ). Results were expressed as median and interquartile range (IC), sensitivity, specificity and predictive values were calculated. P values <0.05 were considered significant.
Results The mean FIQ of 803 patients with FM (792 women and 26 men) was 73.29. The median number of tender points was 16 (IC: 14-18). At the time of the study, 13 patients with FM did not meet the 1990 ACR criteria. Of the patients studied, 665 fulfilled the 2010 ACR criteria and 93 did not meet these criteria (45 did not complete the assessment). From the control groups, patients with RA + OA, 112 met the 2010 ACR criteria and 254 did not meet them. Comparison between FM patients who fulfilled the 2010 ACR criteria and those who did not fulfill the criteria showed significant differences in the number of tender points (p<0.03), FIQ (p<0.001), WPI (p<0.001), SS1 (p<0.001), SS2 (p<0.001) and short symptom severity (p<0.0001). Sensitivity of the Spanish version of the modified 2010 ACR criteria was 87.7% (95% IC: 85.3 to 90.1), specificity 69.4% (95% IC: 64.5 to 74,3), positive predictive value 85.6% (95% IC: 83.0 to 88.1) and the negative predictive value 73.2% (95% IC: 68.4 to 78.0).
Conclusions Although sensitivity result (87.7%) was slightly lower than in the original study (sensitivity 88.1%), the high specificity and predictive values of the Spanish version of this questionnaire make it useful in facilitating diagnosis and evaluation of patients with FM.
Disclosure of Interest : None declared