To validate the 2013 ACR/EULAR classification criteria for systemic sclerosis (SSc) in patients from a capillaroscopy clinic.
All patients attended in a capillaroscopy clinic were included. Sociodemographic and SSc-related variables were collected. Using as gold standard for SSc the clinical judgement, the performance (sensitivity, specificity, predictive values, and likelihood ratios) of the 2013 ACR/EULAR criteria were analyzed. Receiver operating characteristic (ROC) curve and the area under the curve (AUC) were calculated for the global score and individual items, and the best cutoffs were obtained.
We included 327 patients (84% women, mean age at capillaroscopy 48 years). Main reasons for capillaroscopy referral were Raynaud's phenomenon (39%) and SSc evaluation (27%). The most frequent final clinical diagnosis were SSc (32.4%) and primary Raynaud's phenomenon (25.7%). The 2013 ACR/EULAR SSc classification criteria were met by 116 patients (35.5%). Sensitivity and specificity of the new criteria were 98.1% and 94.6%, respectively, and positive and negative predictive values were 89.7% and 99.1%. The individual variables with the best sensitivity were Raynaud's phenomenon (99.1%) and abnormal nailfold capillaries (81.1%). All the individual variables, except Raynaud's phenomenon, puffy fingers and sclerodactily showed high specificity values, over 90%. The best cutoffs of the total score were ≥8, ≥9, and ≥10, and the AUC = 0.993.
We validated the new ACR/EULAR classification criteria for SSc in unselected patients from a capillaroscopy clinic. Global score and individual items included in the new criteria show high diagnostic accuracy and discriminatory capacity.