The difficulty in determining synovitis, tenosynovitis, or enthesitis by physical examination (PE) has limited the diagnostic capability of CASPAR for psoriatic arthritis (PsA). Therefore, we aimed to evaluate the diagnostic utility of CASPAR with the integration of ultrasound (US).
Patients with a hint of PsA were enrolled. Besides routine PE for tender or swollen joints, enthesitis, and dactylitis, US was performed to evaluate peripheral joints, entheses, and tendons. The additional value of the US to the CASPAR criteria was analyzed.
A total of 326 consecutive patients with 164 PsA and 162 non-PsA were enrolled. A total of 162 non-PsA patients consisted of 58 cases of psoriasis (PsO), 27 osteoarthritis with PsO/family history of PsO, five fibromyalgia with PsO, 69 sero-negative rheumatoid arthritis, and three undifferentiated arthritis. Significantly higher frequencies of tenosynovitis and enthesitis on US and new bone formation on X-rays were found in PsA vs. non-PsA patients (59.1%
The diagnostic utility of the CASPAR was improved by integrating tenosynovitis and/or enthesitis when using US. US provides additional value for PsA recognition.