Delays in Diagnosis, Infrequent Disease Activity Monitoring Observed in PsA, axSpA

Andrew Concoff, MD

Credit: Exagen Inc.

Real-world challenges of identifying cases of psoriatic arthritis (PsA) and axial spondyloarthritis (axSpA) in the United States were associated with high rates of diagnosis with other inflammatory conditions at baseline, as well as delays in receiving a definitive diagnosis, according to research presented at the 2023 Congress of Clinical Rheumatology West.¹

Investigators believe an increase in diagnostic imaging in conjunction with a more consistent application of disease activity measures may help to guide treatment decisions, such as a treat-to-target strategy, and improve quality of care.

“There is limited literature providing a comprehensive view of the care journey of patients with PsA or axSpA within rheumatology clinics in the US,” wrote lead investigator Andrew Concoff, MD, FACR, CAQSM, executive vice president, chief medical officer at United Rheumatology, and colleagues.

To better understand the real-world clinical journey of this patient population, investigators analyzed data from the United Rheumatology Normalized Integrated Community Evidence (UR-NICE) database between April 2015 and March 2020. Eligible patients were adults with ≥2 rheumatology visits with a PsA or axSpA diagnosis between 30 – 365 days apart. The first rheumatology visit was considered the index, and baseline was from the earliest record up to the day before index.

Demographics, diagnosis and treatment patterns, and clinical characteristics were collected and evaluated. Only results from index on or after January 2017 were assessed to account for the effects of the new interleukin (IL)-17 inhibiting treatments introduced in 2016.

A total of 9201 patients with PsA and 3131 patients with axSpA had baseline characteristics available for analysis. A baseline history of chronic inflammatory conditions was observed in 68% (n = 6259) of patients in the PsA cohort and 49% (n = 1546) of patients in the axSpA group.

Approximately half (49%) of patients with PsA were diagnosed at first visit; however, undiagnosed patients received a diagnosis an average of 96 days after this visit. Similarly, 45% of patients with axSpA were able to be diagnosed at the first rheumatology visit, while undiagnosed patients waited an average of 89 days from first visit to diagnosis.

All patients had ≥1 record of disease activity measures either pre- or post-diagnosis. However, the use of these measures was low. For example, Disease Activity Score in 38 Joints (DAS28) and Simplified Disease Activity Index (SDAI) were reported in <10% of patients with PsA pre-diagnosis and only <14% post-diagnosis. Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) and Ankylosing Spondylitis Disease Activity Score (ASDAS) were reported in <12% of patents with axSpA prior to their diagnosis and <20% post-diagnosis. Of the measures reported, general pain (≥78%) was the most common among both groups.

Regarding medication usage, tumor necrosis factor inhibitors (TNFs) were the most prescribed medication (≥54%) following a diagnosis. In both populations, an increase in biologic/targeted synthetic disease-modifying antirheumatic drug (b/tsDMARD) prescription was the highest (+50%) post-diagnosis and opioid prescriptions were the lowest.

Investigators noted limitations including potential inaccuracies in electronic medical records due to patients’ recall bias and miscoding. Additionally, medication information was not verified by a pharmacy or usage data, and instead relied on prescription data from these records. The low prevalence of chronic inflammatory conditions at baseline compared with other data sources, as well as the low utilization of imaging diagnosis may be related to general underreporting and the expected incompleteness of real-world data. Lastly, investigators only included medical information from clinicians registered in the UR-NICE database.

References

1. ^{Joshi R, Beaty S, Concoff A, et al. Rheumatology Care Journey Among Patients with Psoriatic Arthritis or Axial Spondyloarthritis in the United States. Congress of Clinical Rheumatology. September 2023.}