Validation of EULAR primary Sjogren's syndrome disease activity (ESSDAI) and patient indexes (ESSPRI)
Objectives To validate the two recently developed disease activity indexes for assessment of primary Sjogren's syndrome (SS): the European League Against Rheumatism (EULAR) SS Patient Reported Index (ESSPRI) and the EULAR SS Disease Activity Index (ESSDAI). Methods A prospective international 6-month duration validation study was conducted in 15 countries. At each visit, physicians completed ESSDA