Background/Purpose: Anti-cyclic citrullinated peptide antibody (Anti-CCP) is a diagnostic tool that predicts the progression of undifferentiated polyarthritis and erosive disease in rheumatoid arthritis (RA). It is more sensitive (60%) and specific (98%) than rheumatoid factor (RF). Despite these advantages, we hypothesize that physicians underutilize anti-CCP and other diagnostic tests for RA, which results in delay of diagnosis of RA and delay of initiation of treatment with disease modifying anti-rheumatic drugs. We aimed to describe the primary care work-up of polyarthritis in patients who eventually received a diagnosis of RA.

Methods: We performed retrospective chart review in patients seen between 1/1/2010 and 6/15/2014 in two rheumatology clinics, one private practice and one in a community health center associated with an academic medical center.

Results: We identified 173 patients seen in one of two rheumatology clinics referred from 141 different primary care providers. The sample was 83% (n=143) female, and the mean±SD age was 55.5±18.6 years. The majority (75.7%) were treated at the private practice. Anti-CCP or RF was ordered by the referring provider (prior to presentation to the rheumatologist) in only 38.7% (95% CI 31.7%, 46.3%) of patients. The presence of anti-CCP or RF did not vary significantly by presenting site: 33.3% at the community health center vs. 40.5% at the private practice, p=0.47. Ordering of anti-CCP varied non-significantly by presenting site: 19.1% of patients at the community health center presented with anti-CCP compared to 32.1% of the patients seen at the private practice (p=0.12). Prior to presentation at the rheumatology clinics, ESR was ordered in 43.9% of patients and CRP was ordered in 33.0% of patients. Ordering of ESR and/or CRP varied by site: 28.6% of patients seen at the community health center presented with ESR or CRP, but 52.7% at the private practice (p=0.008) presented with ESR or CRP. Lyme titre was ordered in 0.0% of community health center patients vs. 9.6% of private practice patients, p=0.04. Radiological imaging performed by PCP was only documented for 38.2% (n=66) of patients, with x-ray being the most frequent (46/66 or 69.7%) and MRI a distant second (6/66 or 9.1%). Functional ability was documented in only 2.3% of referred patients (95% CI 0.9%, 6.1%). About half of all patients (68, 51.1%) had DMARDS initiated immediately on presentation to the rheumatologist. Interval to treatment ranged from 0 weeks to 144, but only 18.1% (n=24) waited longer than one month for treatment. Interval to treatment was not associated with CCP order by referring physician (50% waiting > 1 month if anti-CCP was ordered vs. 30.3% if anti-CCP was not, p=0.13).

Conclusion: Most primary care physicians failed to order diagnostic tests for RA prior to referring a patient with polyarthritis to a rheumatology clinic. In particular, primary care providers failed to order anti-CCP in 61% of referred patients who eventually received a diagnosis of RA. Failure to order anti-CCP did not appear to significantly delay initiation of treatment of RA. These findings suggest educational efforts should focus on emphasizing earlier diagnostic workup, especially anti-CCP, in patients suspected to have RA.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/use-of-rheumatologic-testing-by-primary-care-physicians-in-patients-with-inflammatory-arthritis/