Association between patient perception of disease status and different components of the Minimal Disease Activity (MDA) criteria in psoriatic arthritis

Objective: The aim of this analysis was to evaluate the relationship between the criteria met of the Minimal Disease Activity (MDA) score for psoriatic arthritis (PsA) and patient-perceived disease status.

Methods: We analysed data from the ReFlaP study (NCT03119805), a cross-sectional international study of adult patients with PsA. Patients self-reported if they felt their PsA was in remission (REM), low disease activity (LDA) or neither. The relationship between patient-reported status and MDA domains met was analysed using point biserial correlation, chi-square test (Χ2), odds ratio, and specificity.

Results: 88.4% of study patients who met MDA reported good disease status (REM/LDA). Pain was the most commonly missed domain for these patients. A moderate to strong correlation was found between meeting more MDA domains and patient-reported good status irrespective of domain missed. On individual domain testing, MDA state and patient-reported REM/LDA were significantly associated irrespective of domain missed with the exception of enthesitis. Specificity of the MDA score irrespective of domain missed was above 90%. The odds of MDA patients reporting poor disease status was significant only for when pain < 1 was the unmet domain. This significance was not supported by sensitivity analysis.

Conclusion: This study suggests strong agreement between MDA status and patient-reported good status irrespective of domain missed. Pain < 1 or 2 on a 0-10 numerical rating scale was the hardest domain to meet. The high specificity regardless of the unmet domain suggests patients who feel their disease is active are minimally misclassified by the score.