Psoriatic arthritis is a chronic inflammatory disease that can affect the joints, tendons and entheses, which are the sites where tendons and ligaments attach to bone. Several targeted treatments are available, but they work through different biological pathways and may not act with the same speed on musculoskeletal inflammation.

In this real-world study, we evaluated patients with active psoriatic arthritis who were starting or switching a biologic or targeted synthetic treatment. Patients received TNF inhibitors, JAK inhibitors, IL-17 inhibitors or IL-23/IL-12/23 pathway inhibitors. We used musculoskeletal ultrasound to measure inflammation over time, focusing on pragmatic ultrasound scores called MIJET and 2MIJET. These scores are designed to capture inflammatory changes in clinically relevant joint, entheseal and tendon sites.

The main aim was to compare how quickly ultrasound inflammation improved across the different treatment classes. Overall, ultrasound monitoring showed that early changes were clinically informative. Patients who maintained treatment over time had greater improvement in MIJET and 2MIJET during follow-up than those who discontinued treatment. Baseline ultrasound burden alone was less useful, while dynamic ultrasound changes were more informative.

When comparing treatment classes, JAK inhibitors showed the fastest early ultrasound improvement, particularly at 1 month. TNF, IL-23 and IL-17 inhibitors showed more gradual early changes.

These findings suggest that musculoskeletal ultrasound may help detect early differences in treatment response across mechanisms of action. Pragmatic ultrasound scores could complement clinical assessment and support short-term treatment monitoring in patients with psoriatic arthritis.