Uncovering SpA in Patients Initially Diagnosed with Polymyalgia Rheumatica

8/14/2025

A study recently published in Arthritis & Rheumatology explored the link between polymyalgia rheumatica and spondyloarthritis.

Polymyalgia Rheumatica (PMR) is an inflammatory condition that usually affects older adults, causing pain and stiffness mainly around the shoulders and hips. However, some patients initially diagnosed with PMR are later found to have spondyloarthritis (SpA), which also involves inflammation but typically affects the spine and joints where tendons attach to bones. The conditions share some similarities in symptoms and imaging findings, making diagnosis difficult.

Researchers looked at patients treated at a hospital in Leeds from 2002 to 2024 who were first diagnosed with PMR but later reclassified as having SpA. They included patients who met established criteria for PMR at the time of their initial diagnosis. The study found 31 such patients, with a median age of 62 years, including both men and women.

Some patients were diagnosed with SpA quickly after their initial symptoms appeared, while others were diagnosed years later. MRI testing often showed characteristic signs of SpA on MRI, such as inflammation in the spine and sacroiliac joints, as well as bone marrow edema in the spine. Most patients initially responded well to steroid treatment commonly used for PMR, but some experienced flares or ongoing inflammation despite steroid treatment. Those patients who experienced ongoing inflammation often required additional treatments beyond steroids, including Disease-Modifying Antirheumatic Drugs (DMARDs) and biologics targeting TNF-alpha and IL-17.

The study suggests that in some older patients, symptoms that look like PMR may actually be a form of SpA or an overlap of both conditions. This overlap might explain why some patients don’t respond well to steroids alone and benefit from biologic therapies used for SpA. The researchers assert that understanding this connection can help doctors tailor treatment better for patients with these complex symptoms.

References

• American College of Rheumatology – Late-Onset Spondylarthritis Presenting as Glucocorticoid-Resistant Polymyalgia Rheumatica
• SAA – Episode 90 | Personalized Medicine in Spondyloarthritis: The Role of Biomarkers
• NIH – Polymyalgia Rheumatica and Giant Cell Arteritis: Diagnosis, Treatment, and Steps to Take