The Minimal Disease Activity (MDA) uses the Health Assessment Questionnaire (HAQ) as one criterion. HAQ does not correlate well with disease activity with increased PsA disease duration, and its use in the MDA has been questioned. The Psoriatic Arthritis Impact of Disease (PsAID) was specifically developed for PsA Patients. We aimed to validate the PsAID within our patient cohort and determine if the PsAID can replace the HAQ in the MDA.
Patients were recruited from the PsA clinic and assessed according to a standard protocol including demographics, clinical features and laboratory tests. Descriptive statistics were calculated. PsAID cut-offs for use in the MDA were generated based on the Clinical Disease Activity for Psoriatic Arthritis (cDAPSA).
115 patients completed the PsAID. There were 70 males, 45 females, with a mean PsA duration of 18.7 (±11.6) years. Mean scores of PsAID-9 and PsAID-12 were 3.4 (±2.4) and 3.2 (±2.3), respectively. The PsAID correlated moderately well with 9 of the PROMs administered in the clinic (ρ = 0.51-0.78). Four PsAID cutoffs based on cDAPSA were generated for use in the MDA: remission (REM) PsAID-9, REM PsAID-12, low disease activity (LDA) PsAID-9, and LDA PsAID-12. All four versions of the PsAID MDAs had sensitivity greater than 85% with the HAQ-MDA, and three versions of the PsAID-MDA had specificity greater than 85% with the HAQ-MDA.
The high sensitivity and specificity of the PsAID-MDA with the HAQ-MDA suggest that the PsAID is an effective replacement for the HAQ in the MDA.