TOPLINE

Osteoarthritis (OA) was associated with the risk of developing inflammatory arthritis immune-related adverse events (IA-irAEs) in patients with cancer receiving immune checkpoint inhibitor (ICI) therapy. Among ICI-treated patients, 69% of those who developed IA-irAEs had OA, with hand OA being the predominant pattern in those with IA-irAEs.

METHODOLOGY

• Researchers conducted a retrospective study at Mayo Clinic in Minnesota to compare the prevalence of OA among ICI-treated patients with cancer between January 2015 and June 2025, including 181 patients with de novo IA-irAEs, 140 with other irAEs without IA (non-IA irAE), and 170 without any irAE (non-irAE).
• Patients were adults (mean age, 65.6 years; 57% men) with malignancy who received any ICI therapy (anti–PD-1, anti-PD-L1, or anti-cytotoxic T-lymphocyte-associated protein 4 blockade) as monotherapy or combined therapy.
• Two control groups (non-IA irAE and non-irAE) were frequency matched for age, sex, BMI, and smoking status.
• Electronic medical records were reviewed to extract demographic data, disease-related information including cancer type and stage, ICI regimen, irAE type, OA history and joint involvement patterns, and laboratory results.
• OA was retrospectively ascertained on the basis of diagnoses documented in medical records.

TAKEAWAY

• The prevalence of OA was significantly higher at 69% vs 48% in the IA-irAE group vs the non-IA irAE group and non-irAE group (P < .001 for both), with this difference remaining significant across age groups of below 65 years and 65 years or above.
• Among ICI-treated patients with OA, hand OA was the predominant pattern observed in 62% vs only 13% of those in the IA-irAE group vs the non-IA irAE with OA group and non-irAE with OA group (P < .001 for both), whereas knee OA was more common in the non-IA irAE with OA group and non-irAE with OA group at 51% and 41%, respectively.
• Preexisting OA was independently associated with IA-irAE development (odds ratio [OR], 2.88; 95% CI, 1.85-4.52), as were a family history of autoimmune disease (OR, 2.03; 95% CI, 1.02-4.05) and melanoma diagnosis (OR, 2.63; 95% CI, 1.56-4.47).
• Patients who developed IA-irAEs demonstrated better cancer outcomes, with a remission rate of 47% than 31% in those in the non-IA irAE group and 22% in those in the non-irAE group (P < .01).

IN PRACTICE

“[The study] findings suggest that preexisting hand OA may be predisposed to the development of polyarticular IA-irAE rather than reflecting a nonspecific consequence of ICI exposure,” the authors of the study wrote.

SOURCE

The study was led by Shiju Chen, MD, Department of Medicine, Mayo Clinic, Rochester, Minnesota. It was published online on June 01, 2026, in Arthritis Care & Research.

LIMITATIONS

OA identification relied on retrospective documentation rather than systematic joint screening, and variations in imaging availability may have influenced OA detection rates. Site-specific prevalence could have been affected by documentation practices, potentially introducing detection bias. IA-irAE cases managed without specialty referral may have been underrecognized because only patients evaluated by rheumatologists were included. Residual confounding related to treatment selection cannot be ruled out.

DISCLOSURES

The study received support from the National Institutes of Health through grants to an author, along with funding from the Mark E. and Mary A. Davis Initiative in Rheumatoid Arthritis Research and Mayo Foundation for Medical Education and Research. Two authors reported receiving grants or contracts from other organizations.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.