A recent study examined the risk of developing inflammatory arthritis in patients with psoriasis initiating biologic treatments.

In the retrospective analysispublished in the Journal of the American Academy of Dermatology, investigators used a large U.S. payer claims database—the Optum Clinformatics Data Mart database—to examine the data of 7,345 patients with psoriasis who initiated biologic treatment between January 2014 and March 2023.

They compared the incidence of inflammatory arthritis among four treatment groups:

• Interleukin (IL)-23 inhibitors (n = 2,712): guselkumab, risankizumab, and tildrakizumab
• IL-17 inhibitors (n = 811): brodalumab, ixekizumab, and secukinumab
• IL-12/23 inhibitors (n = 1,078): ustekinumab
• Tumor necrosis factor (TNF) inhibitors (n = 2,744): adalimumab, certolizumab, etanercept, and infliximab.

Inclusion criteria required patients to be 18 years or older, with ≥ 2 ICD-9/ICD-10 diagnosis codes for psoriasis. Exclusion criteria comprised prior biologic or methotrexate treatment, preexisting psoriatic arthritis or inflammatory arthritis diagnoses, and rheumatologist visits before the index treatment.

Patient characteristics varied slightly among groups. The mean age ranged from 44.68 years (standard deviation [SD] = 15.43) for the IL-12/23 inhibitor group to 50.66 years (SD = 15.31) for the IL-17 inhibitor group. Female representation ranged from 46.28% in the IL-23 inhibitor group to 50.92% in the IL-17 inhibitor group.

Patients were followed for up to 3 years or until the development of inflammatory arthritis, treatment switch/discontinuation, or loss of follow-up. The primary analysis used a Cox proportional hazards model, adjusting for baseline characteristics such as age, sex, race, region, psoriasis duration, hospitalizations, Charlson comorbidity score, and relevant comorbidities such as cardiovascular diseases, hypertension, chronic obstructive pulmonary disease, diabetes, obesity, liver disease, renal disease, baseline apremilast use, and joint pain any time prior to index biologic treatment.

The investigators revealed that patients treated with IL-23 inhibitors had a lower risk of developing inflammatory arthritis, including psoriatic arthritis, compared with those receiving other biologic therapies.

Incidence rates of inflammatory arthritis (events per 100 person-years):

• IL-23 inhibitors: 4.99 (95% confidence interval [CI] = 4.10–6.07)
• IL-17 inhibitors: 7.29 (95% CI = 5.64–9.45)
• IL-12/23 inhibitors: 6.06 (95% CI = 4.72–7.81)
• TNF inhibitors: 9.39 (95% CI = 8.27–10.68).

Adjusted hazard ratios for developing inflammatory arthritis (compared with IL-23 inhibitors):

• IL-17 inhibitors: 1.44 (95% CI = 1.04–2.01, P = .0294)
• TNF inhibitors: 1.90 (95% CI = 1.50–2.42, P < .0001).

Similar trends were observed for the risk of developing specifically psoriatic arthritis.

The investigators conducted several sensitivity analyses to increase the robustness of their findings:

• Requiring at least two instances of ICD-9/ICD-10 codes for inflammatory arthritis diagnosis
• Expanding the start of the outcome follow-up period to 3 months post–index treatment initiation
• Expanding the start of the outcome follow-up period to 6 months post–index treatment initiation.

All sensitivity analyses showed similar trends, further strengthening the study's findings.

The investigators noted that their findings were consistent with previous studies implicating IL-12, IL-17, and IL-23 in the development of psoriatic arthritis. Study limitations included the potential for protopathic bias, as clinicians may be more likely to prescribe IL-17 or TNF inhibitors in patients presenting with joint pain or a perceived risk of inflammatory arthritis. The investigators attempted to mitigate this by excluding patients with baseline inflammatory arthritis, methotrexate use, and prior rheumatologist visits.

This retrospective study revealed that patients with psoriasis treated with IL-23 inhibitors were less likely to develop inflammatory arthritis or psoriatic arthritis compared with those treated with IL-17 or TNF inhibitors. These findings may provide valuable insights for health care providers when treating patients who may be at increased risk of developing inflammatory arthritis.

Conflict of interest disclosures can be found in the study.