Questionnaires Point to Need for Psoriatic Arthritis Evaluation

Questionnaires given to patients with psoriasis predicted probable psoriatic arthritis in a significant number of patients.

Psoriatic arthritis screening questionnaires given to patients with psoriasis may help clinicians determine whether assessment by a rheumatologist is necessary, according to the results of a study published online on June 25, 2014, in the Journal of the American Academy of Dermatology.

The screening tools predicted probable psoriatic arthritis in 43% to 45% of participants. Of these patients, 30% were later diagnosed with psoriatic arthritis by a rheumatologist.

Positive predictive value of the tests varied, however. The negative predictive value was high as well, which indicated that the tools work well for identifying patients who do not need additional evaluation.

“A substantial proportion of patients with psoriasis given a diagnosis of [psoriatic arthritis] by a rheumatologist in this study had no history of the condition, suggesting underdiagnosis of this potentially disabling disorder in this population,” wrote the researchers.

Researchers evaluated 3 psoriatic arthritis screening questionnaires: the Psoriasis and Arthritis Screening Questionnaire (PASQ), the Psoriasis Epidemiology Screening Tool (PEST), and the Toronto Psoriatic Arthritis Screen (ToPAS). The researchers selected participants from PREPARE, a multicenter, noninterventional study conducted to estimate psoriatic arthritis prevalence in patients with psoriasis presenting to dermatologists’ offices and to rheumatologists.

Participants with plaque psoriasis were enrolled from 34 dermatology centers in Europe and North America, and were randomly assigned 1 of the 3 screening questionnaires. Evaluation by a rheumatologist confirmed diagnosis of psoriatic arthritis.

The study evaluated 949 patients, with 285 patients receiving a clinical diagnosis of psoriatic arthritis. Among the patients receiving this diagnosis, 59% had previously received a psoriatic arthritis diagnosis, whereas 41% had not.

False-positive rates in all 3 screening questionnaires ranged from 20% to 26% in all patients, which researchers called “surprisingly low.” Differences between the screening tools were small as well.

Despite the array of positive predictive values, the high negative predictive values provide valuable insights for clinicians, the researchers noted.

“The choice of screening tool may therefore depend on other factors, such as feasibility and completion rates, and the use of collateral information,” the researchers wrote. “Based on these findings, the PASQ, PEST, and ToPAS are useful screening tools that can assist dermatologists in identifying patients with psoriasis without [psoriatic arthritis] and patients with possible [psoriatic arthritis] and patients with possible [psoriatic arthritis], who may benefit from further assessment by a rheumatologist.”