Background There have been few studies regarding the way to pick up undiagnosed rheumatoid arthritis (RA) in annual health check examination.
Objectives The purpose of this study it to evaluate the usefulness of rheumatoid factor (RF) and anti-CCP antibody (ACPA) to detect undiagnosed RA in annual health check.
Methods During the period from January 2008 to September 2012, we checked RF in all the patients who visited St. Luke’s International Hospital Center for Preventive Medicine for annual health examinations. Patients who had positive RF with joint symptom and who have highly positive RF (3 times higher than upper limit of normal), with or without joint symptom, are encouraged to be checked ACPA. We retrospectively extracted all the patients who had positive RF, and evaluate the number of newly diagnosed RA and diagnostic utility of ACPA in RF positive population.
Results A total of 34,696 patients were checked RF, and 2210 patients showed positive RF during the study period. Among them, ACPA was checked in 629 patients, and 74 patients had positive result. All the patients who underwent ACPA test were examined by rheumatologist at least once. The diagnosis of RA was made significantly frequent in ACPA positive group (26/74 patients, 35.1%) than in ACPA negative group (19/555 patients, 3.4%, p<0.001) after health check. The sensitivity and specificity of ACPA in this population were 57.8% and 90.2%, respectively.
Conclusions ACPA showed high specificity for diagnosing RA in RF positive population. The combination of RF and ACPA screening in health check can be useful for detecting undiagnosed RA.
Disclosure of Interest None Declared