The aim of this study was to validate the modified 2010 ACR preliminary criteria for FM in a Spanish population.
Five hundred and seventy-nine (550 women) FM and 294 (240 women) control participants were enrolled in the study. FM patients were previously diagnosed by a rheumatologist. All participants underwent both the 1990 ACR criteria (1990c) and the modified 2010 ACR criteria (m-2010c).
The tender points count showed correlations of 0.69, 0.65 and 0.71 with the widespread pain index (WPI), symptoms severity (SS) and polysymptomatic distress (PSD) scales, respectively (all P < 0.001). The WPI, SS and PSD showed greater correlations with impact of FM health-related quality of life, general fatigue and depression than the tender points count. The 1990c showed sensitivity and specificity values of 84.1 and 97.6, respectively, whereas the m-2010c showed values of 88.3 and 91.8, respectively. Both criteria showed the same overall accuracy, with a value of 0.89. When the 1990c and m-2010c were combined and patients had to satisfy one of two criteria to be diagnosed with FM, the sensitivity, specificity and accuracy of questionnaires were 96.7, 89.8 and 0.94, respectively. The original cut-off points (WPI ≥ 7, SS ≥ 5 and PSD ≥ 12) showed the best test characteristics in the present study.
The m-2010c, with the same cut-off points as the original version, are a valid tool for the diagnosis of FM in our population. Whenever possible, the combination of the 1990c and m-2010c is recommended (patients have to meet one of the two criteria to be diagnosed), since this approach showed the best diagnostic characteristics.