The combination of the connective tissue diseases questionnaire plus rheumatoid factor and anti-cyclic citrullinated peptide antibody positivity had a 95% sensitivity and 32% specificity for identifying people with at least one swollen joint at free community health fairs.
The study, presented at the Western Regional Meeting of the American Federation for Medical Research, is one of few to examine rheumatoid arthritis (RA) screening techniques in the community health fair setting, where more prevalent conditions, such as diabetes receive more attention.
A total of 601 participants were screened at five health fair sites in the greater Denver area administered by the nonprofit 9Health. The researchers administered the 30-item connective tissue diseases questionnaire (Ann. Epidemiol. 1995 Jul;5:297–302) as well as blood tests for rheumatoid factor (RF) and anti-cyclic citrullinated peptide antibody (anti-CCP). Patients also had a joint examination by a rheumatologist who was unaware of the assay and questionnaire results.
The 601 patients who elected to undergo RA screening represented 16% of the total fair attendees, and more than half said they sought RA screening because they had joint symptoms. A television and Internet ad campaign in the region prior to the fairs helped to raise public awareness about RA symptoms and risk factors.
A total of 84 people (14%) had one or more swollen joints that would be consistent with possible inflammatory arthritis, according to Dr. Kevin Deane, the principal investigator on the study. “Of those individuals with one or more swollen joints, nine met at least four ACR criteria for RA but never had a prior diagnosis,” he said.
“An additional 15 people had a swollen joint and RF or CCP positivity, but met fewer than four ACR RA criteria. They may have early RA,” he added. And another 41 people had either RF or anti-CCP positivity but didn't have any arthritis. “So something is going on immunologically, but no arthritis yet,” said Dr. Deane of the division of rheumatology at the University of Colorado, Denver.
The cost of the screening effort is $42 per person. The RF and anti-CCP assays were paid for by Abbott Laboratories, Inc., which was a cosponsor of the fair, along with Quest Diagnostics and GE Healthcare. The authors disclosed no relevant conflicts of interest.