Discriminative Value of Tender Points in Fibromyalgia Syndrome

Objective. The aim of this study is to assess the discriminative value of all tender points, alone and in combination, that are designated as criteria for fibromyalgia diagnosis by the American College of Rheumatology (ACR), by investigating the appropriate pressure magnitude that should be applied during tenderness examination. Design. Cross-sectional. Patients. This study was performed on 66 patients with fibromyalgia diagnosed according to ACR classification criteria and 50 control subjects. Setting. The outpatient rheumatology clinic of a PM&R department of a university hospital. Intervention. Pressure pain threshold values were measured by a dolorimeter on nine specific point pairs in both groups and a cutoff value for discriminating positivity and negativity was calculated for each. Then the most valuable tender point pairs were assessed for discrimination of fibromyalgia syndrome using ACR criteria set as a reference standard. Results. All tender points with determined pressure cutoff values were found out to significantly discriminate fibromyalgia syndrome and their area under curve values ranged from 0.779 to 0.934. Univariate logistic regression analysis revealed that lateral epicondyle and supraspinatus point pairs had the most powerful discriminative ability (odds ratio = 113.6 and 45.0, respectively). Multiple logistic regression analysis with backward stepwise method showed that lateral epicondyle and second rib point pairs were most discriminative with sensitivity and specificity rates of 87.9-94.0% and 77.3-84.0%, respectively. Conclusions. Fibromyalgia syndrome can have potential to be recognized simply by pressing fewer tender point areas but with various pressure cutoff levels identified for each tender point areas.