Predictors of Inflammatory Arthritis Among Rheumatology Referrals

The American College of Rheumatology and European Alliance of Associations for Rheumatology recommend that patients with suspected rheumatoid arthritis be assessed by a rheumatologist within 6 weeks of referral. However, given an increasing shortage of rheumatologists and long wait times, this approach is often not possible. Additionally, distinguishing inflammatory from noninflammatory arthropathy is not always straightforward for primary care providers and other referring physicians, leading to an increased number of potential referrals for nonspecific joint pain and longer wait times.

Dr. Brendan Thoms and colleagues sought to identify variables distinguishing inflammatory from noninflammatory arthritis in a large cohort of new rheumatology patients referred to a tertiary academic medical center. Researchers also described the time from referral to initial visit and which clinical characteristics were documented in the referrals.

The study included all adult patients with arthralgia who were referred to the University of Vermont Medical Center’s Division of Rheumatology and who attended 1 clinic visit between January 1 and June 30, 2019. Data were obtained from electronic medical records. Demographics, referral sources, clinical characteristics, and laboratory and imaging results were extracted from the patient’s referral letter and documentation from the patient’s initial rheumatology visit and/or follow-up visit. Examples of variables examined include joint tenderness or swelling on examination, morning stiffness ≥1 hour in duration, patient-reported fatigue or brain fog, a past medical history of psoriasis or inflammatory bowel disease, laboratory results (such as ANA, RF, CCP, HLA-B27, and elevated inflammatory markers), and erosive changes on imaging.

The study found 1023 referrals. The most common referral source was primary care (85.3%), followed by orthopedic surgery (4.9%) and dermatology (2.3%). The majority of referred patients were White (94.2%) and female (70.3%). Of 697 patients referred to rheumatology with arthralgia, 25.7% were diagnosed with inflammatory arthritis. The most common diagnoses associated with noninflammatory arthropathies were osteoarthritis (approximately 50%) and fibromyalgia (approximately 21%).

In the multivariable analysis, morning stiffness (odds ratio [OR], 9.1) and presence of joint tenderness or swelling on examination (OR, 3.4) remained significant as predictors of inflammatory arthritis. Fatigue or brain fog were confirmed to be negative predictors of inflammatory arthritis. Due to a high proportion of missing data, multivariable analyses of laboratory and radiographic findings were not performed.

The median time between referral letter and rheumatology appointment was 8 weeks for patients diagnosed with inflammatory arthritis. Documentation of duration of arthralgia or morning stiffness in referrals was uncommon (31.0% and 20.5%, respectively). A joint examination was documented in only 57% of referrals. While ANA was frequently checked prior to patient referral (48.2%), the most common serologies seen with inflammatory arthritis were checked less frequently, including RF (38.5%), anti-CCP (18.5%), and HLA-B27 (4.3%).

This study showed that the majority of patients referred to rheumatology at this academic medical center did not have inflammatory arthritis; in fact, 3 in 4 patients referred were ultimately diagnosed with a noninflammatory condition. Standardizing the referral process with a referral tool and educating primary care providers about predictors of inflammatory disease could help improve access time for patients with inflammatory arthritis, according to the authors. Additionally, they noted a paucity of relevant information in referrals made appropriately triaging patients with possible inflammatory arthritis more difficult.

The study also found the frequency of ANA testing was high despite its lack of correlation with inflammatory arthritis, and the authors suggested that primary care providers likely misunderstand the utility of the ANA test as a general screening tool for joint pain. Ultimately, better educating referring providers on the utility of serologic testing and the components of history and exam that raise concern for inflammatory arthritis, as well as simplifying triage protocols, may help increase the yield of referrals and reduce wait times for the most vulnerable patients.

 Reference

[1] Thoms BL, Bonnell LN, Tompkins B, Nevares A, Lau C. Predictors of inflammatory arthritis among new rheumatology referrals: a cross-sectional study. Rheumatol Adv Pract. 2023. doi:10.1093/rap/rkad067