Impact of disease duration and gender on the sensitivity and specificity of 2015 ACR/EULAR classification criteria for gout. Cross-sectional results from an Italian multicentric study on the management of crystal-induced arthritis (ATTACk).

Objectives: We aimed to assess the performance of the 2015 American College of Rheumatology/European League Against Rheumatism (ACR/EULAR) gout classification criteria in an Italian cohort of patients with crystal-induced arthritis stratified by disease duration and gender in a real-life setting.

Methods: Consecutive patients referred to Rheumatology Units for suspected acute crystal-induced arthritis were enrolled in a multicentre cohort study by the Italian Society of Rheumatology which was designed to improve the management of crystal-induced arthritis (ATTACk). To test the performance of the criteria (sensitivity and specificity), the presence of monosodium urate (MSU) crystals in synovial fluid (SF) was used as gold standard.