Background The 1980's ACR classification criteria for systemic sclerosis (SSc) show low sensitivity, especially in early or mild forms. A new set of classification criteria has been developed by ACR/EULAR in 2013. Applicability of the new criteria in clinical practice remains to be shown.
Objectives To evaluate the performance of both set of classification criteria for SSc in a Portuguese SSc population.
Methods Cross-sectional study including consecutive patients with clinical diagnose of SSc (based on expert opinion) followed in our rheumatology department. Clinical and demographic characteristics were collected by consulting the clinical files and national data base – Reuma.pt. The two sets of criteria were applied to all patients, sensitivity was calculated and Kappa coefficient was used to evaluate the agreement between them. Patients not fulfilling the old but fulfilling the new criteria were compared with those that fulfilled ACR criteria using Mann-Whitney, qui-square and fisher test (SPSS 23.0). Significance level was set as <0.05.
Results 108 patients were included, 96 (88.9%) were female with mean age of 58.21 (±12.8) years and a median disease duration of 6 years (0–38). 96 (88.9%) had localized and 12 (11.1%) had diffuse disease form. The most prevalent criteria items were: Raynaud's phenomenon (93.5%), sclerodactyly of the fingers (85.2%) and antinuclear antibodies (94.4%).
For overall cohort, 53 patients (49.1%) fulfilled the old ACR criteria. These 53 patients and more 44 patients (97) fulfilled the new ACR/EULAR criteria, showing a sensitivity of 89.9% compared to 49.1% of the old ones. Kappa coefficient was 0.197 (p=0.01).
In patients with localized forms, the sensitive of ACR/EULAR criteria was 88.5% compared with 43.8% of ACR 1980 criteria and Kappa coefficient was 0.183 (p=0.02).
In diffuse forms, all 12 patients fulfilled both criteria set, showing an almost perfect agreement.
Patients not fulfilling the old but fulfilling the new criteria presented more frequently with capillaroscopic abnormalities (p=0.04) and anticentromere antiboy (p=0.01), but low incidence of anti-Scl70 antibodies (p<0.001) and interstitial lung disease (p<0.001).
Conclusions Our study confirmed a greater sensibility of the new ACR/EULAR 2013 criteria compared with ACR 1980 criteria, especially in mild and localized SSc disease forms. In our patients with SSc not fulfilling the old criteria, the presence of capillaroscopic abnormalities and anticentromere antibodies among the new set of classification criteria were of the utmost importance in their reclassification as SSc patients. The application of the new criteria in clinical scenario allows an early classification and timely management of more SSc patients, ensuring a better prognosis.
Disclosure of Interest None declared