PASDAS Cutoff for Minimal Disease Activity in PsA Is Determined

Authors of a new study have validated a cutoff value of the Psoriatic Arthritis Disease Activity Score (PASDAS) that defines minimal disease activity (MDA) state. According to the researchers, a PASDAS greater than 3.2 reflects MDA. 

To reach this conclusion, 178 patients with psoriatic arthritis (PsA) were prospectively recruited from the University of Toronto PsA clinic. The patients—53.9% of whom were men—had a mean PASDAS of 3.29; 47.8% of the patients had MDA.

To determine the optimal PASDAS cutoff that would signal whether or not patients were in MDA state, the researchers used a receiver-operating characteristic (ROC) curve analysis.

The ROC curve analysis identified a PASDAS score of 3.2 as the point that maximized the sensitivity and specificity for MDA based on meeting 5 of the 7 criteria; there was a sensitivity of 88%, a specificity of 92%, and an area under the curve of 0.96.

For MDA based on meeting 6 of the 7 criteria, a PASDAS score of 2.6 maximized sensitivity and specificity. For MDA based on meeting all 7 criteria, a PASDAS score of 2.1 maximized sensitivity and specificity.

To validate previously proposed PASDAS disease activity cutoff scores, the researchers determined the proportion of patients requiring treatment escalation—a surrogate of active disease—in each of the low, moderate, and high disease activity groups.

“An increasing proportion of patients from low to moderate to high disease activity groups required treatment escalation, increasing from 8.1% to 42% to 67%, respectively,” according to the researchers.

—Colleen Murphy

Reference:

Perruccio AV, Got M, Li S, Ye Y, Gladman DD, Chandran V. Treating psoriatic arthritis to target: defining the Psoriatic Arthritis Disease Activity Score that reflects a state of minimal disease activity. J Rheumatol. 2020;47(3):362-368. https://doi.org/10.3899/jrheum.181472.