Psoriatic arthritis (PsA) is a highly heterogeneous disease that can be difficult to diagnose, which is important because a delay in diagnosis of just 6 months has been shown to increase risks of joint erosions, damage, and disability. Yet in one study, 41% of patients in a dermatology clinic who had never been diagnosed with PsA were found to have the disease when screened with medical history, physical examination, and laboratory testing.
“Currently, we are missing a lot of patients,” said Joseph Merola, MD, of Brigham and Women’s Hospital in Boston in a webcast sponsored by the Autoimmune Learning Network.
Screening and Referral
Multiple challenges exist in the diagnosis of PsA, according to Merola. Along with the heterogeneity, these include the fact that it’s a clinical diagnosis — there is no diagnostic test — and there is relatively limited awareness of PsA among non-rheumatologists, he said.
Therefore, a variety of validated screening tools have been developed that typically are used in the primary care or dermatology settings. One of these is the five-question Psoriasis Epidemiology Screening Tool (PEST). If responses to three or more of the questions are positive, the patient should be referred to a rheumatologist:
- Have you ever had a swollen joint or joints?
- Has a doctor ever told you that you have arthritis?
- Do you fingernails or toenails have holes or pits?
- Have you ever had pain in your heel?
- Have you had a finger or toe that was completely swollen and painful for no apparent reason?
Another tool that can be used to evaluate whether the patient should be referred, or if a patient on treatment considers the current state of disease as acceptable or not, is the Psoriatic Arthritis Impact of Disease questionnaire (PSAID12), which rates multiple aspects of disease with 12 questions, including pain, fatigue, work and/or leisure activities, sleep disturbances, coping, anxiety, social participation, and depression. Ratings range from “none” to “extreme,” with final scores being zero to 10. A score below four generally is considered a patient-acceptable state, with higher scores suggesting that referral or a change in treatment should be considered.
The rheumatology evaluation then focuses on the history, physical examination, laboratory testing, and imaging directed by the clinical findings. “We don’t want to expose the patient to excessive radiation,” said M. Elaine Husni, MD, of the Cleveland Clinic. “If the knee is swollen and has limited range of motion, we’ll focus on the knee. If the wrist is swollen and doesn’t move well we’ll start with imaging of the wrist and hands,” she said in an interview.
“We also initially determine whether the disease is mild, moderate, or severe, which helps us with initial treatment decisions,” she said. “We’re …….