The second version of the Toronto Psoriatic Arthritis screen performed well at identifying psoriatic arthritis in 336 psoriasis patients, 131 psoriatic arthritis patients, and 89 individuals in the general population, according to Dr. Brian Tom and his associates.
The sensitivities of the capped and uncapped version of the ToPAS 2 system were the same across all measured groups (92.0%) when the cutpoint was 7 for ToPAS2_cap and 8 for ToPAS2_uncap, although the sensitivity for ToPAS2_uncap was slightly lower when the cutpoint was 9 (84.0% vs. 87.2)%. Both were higher than the original ToPAS index (sensitivity 86.6%), which did not include a spinal domain. However, the specificity of the original ToPAS index across all measured groups was slightly higher (80.5%-95.5%) than with ToPAS2_cap and ToPAS2_uncap (73.8%-89.9% and 71.6%-91.0%).
Besides the addition of a spinal domain, the ToPAS 2 “incorporates further pictures of cutaneous psoriasis, joint inflammation, and dactylitis to improve its performance, as well as more carefully worded questions regarding spinal involvement,” the investigators wrote.
While the specificity is lower with ToPAS 2, this should not be a major issue, because “for the purposes of identifying patients whom dermatologists or primary care physicians should refer to a rheumatologist, the specificity is not as important, because patients with rheumatological disorders other than PsA would benefit from a rheumatologist’s consultation,” the investigators said.
Find the full study in Journal of Rheumatology (doi:10.3899/jrheum.140857).