Use of Rheumatologic Testing in Patients who Eventually Receive a Diagnosis of Rheumatoid Arthritis

Dilpreet K. Singh, MD; Jasdeep Badwal, MD; Ritika Vankina, MD; Santhi Gokaraju, MD; Jennifer Friderici, MS; Scott Halista, MD; Tara Lagu, MD, MPH

Disclosures

South Med J. 2019;112(10):547-550. 

In This Article

Abstract and Introduction

Abstract

Objectives: Anti-cyclic citrullinated peptide antibody (ACPA) has excellent specificity and prognostic value in patients with early rheumatoid arthritis (RA). The American College of Rheumatology included ACPA in their 2010 classification criteria for RA, but we hypothesize that primary care physicians (PCPs) underuse ACPA, even when clinical suspicion for RA is high. We aimed to describe their use of diagnostic testing in patients who were referred to a rheumatologist and eventually diagnosed as having RA.

Methods: In this retrospective cohort study, a systematic abstraction tool was used to review the medical records of patients seen between January 1, 2010 and June 15, 2014 in two rheumatology clinics: one private practice and one community health center associated with an academic medical center. For purposes of hypothesis generation, we compared the characteristics of patients with and without testing using unpaired t tests or Fisher exact tests.

Results: We identified 173 patients with RA referred from 141 different PCPs: 82.7% were women with a mean ± standard deviation age of 55.5 ± 18.6 years. ACPA and rheumatoid factor were ordered in 28.9% (95% confidence interval 22.6–36.2) and 41.0% (95% confidence interval 33.9–48.6) of patients, respectively. Imaging was underused. Almost half (45.7%, or 37/81) of the patients with documented symptom duration had a delay of at least 1 year before referral; however, ACPA utilization was not associated with the delay to treatment initiation.

Conclusions: Most PCPs failed to order diagnostic tests for RA before referring a patient with polyarthritis who eventually received a diagnosis of RA. We also observed delays in diagnosis, with half of the patients waiting >1 year from symptom onset to diagnosis. These findings suggest educational efforts for PCPs should focus on emphasizing earlier diagnostic workups, especially ACPA, in patients suspected to have RA.

Introduction

Rheumatoid arthritis (RA) is a chronic debilitating inflammatory disease that affects 1% of adults, significantly transforming quality of life and socioeconomic productivity, and uncontrolled RA imposes both physical and emotional limitations.[1] The healthcare and socioeconomic costs associated with RA complications and comorbidities are high.[1–4] Anti-cyclic citrullinated peptide antibody (ACPA) is a diagnostic tool that predicts an increased risk of progression from undifferentiated arthritis to RA. Prior research has demonstrated that in patients with early RA, the prevalence of ACPA is between 34% and 48%, whereas the prevalence of rheumatoid factor (RF) positivity is 50% to 66%.[5–9] In contrast, patients who do not receive a diagnosis of RA have an ACPA prevalence of 3% to 9% and an RF positivity estimated between 7% and 13%.[5–9] As such, the presence of ACPA may be a harbinger for the development of RA, making it a valuable diagnostic tool (the reported positive predictive value is 96.6%).[10–12]

Various interactions with the environment and genetic factors contribute to ACPA formation and disease progression.[10,11,13] Although the differential diagnosis of polyarthritis is broad and includes RA, crystal arthritis (calcium pyrophosphate dihydrate deposition disease and gout), spondyloarthritis (including psoriatic arthritis and reactive arthritis), connective tissue disease–associated inflammatory arthritis, and osteoarthritis, ACPA is a particularly specific test (90%–95%).[5–9] Its presence allows the early identification of RA, which leads to earlier remission, fewer disease complications, and fewer socioeconomic consequences for the patient.[7,12,14–20] Because of this, the American College of Rheumatology and the European League Against Rheumatism included ACPA in their 2010 RA classification guidelines.[21] Although this recommendation is now nearly a decade old, primary care physicians (PCPs) may still be unaware of the importance of initiating evaluation with ACPA and RF when there is a clinical suspicion of RA. We aimed to describe the proportion of patients who presented to a rheumatology clinic with the results of diagnostic testing (ACPA, RF, and imaging). We hypothesized that PCPs underuse ACPA and other diagnostic tests for RA, which could contribute to delays in the diagnosis and treatment of RA.

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