Assessing internal construct validity of DAPSA and DAPSA28 in psoriatic arthritis: a European observational study using confirmatory factor analysis and additional psychometric testing.

ABSTRACT:

Objectives

The Disease Activity index for Psoriatic Arthritis (DAPSA) was developed to assess disease activity in patients with psoriatic arthritis (PsA). A modified version, DAPSA28, uses 28 joints instead of 66/68. This study evaluated key psychometric properties of DAPSA and DAPSA28.

Methods

Data from 1865 patients with PsA in the European Spondyloarthritis (EuroSpA) Research Collaboration Network, having DAPSA and DAPSA28 scores at baseline and follow-up, were analysed. Tests included assessment of internal construct validity by scree plots, confirmatory factor analysis (CFA) and structural equation modelling (SEM), supplemented by tests of differential item functioning (DIF) and evaluation of internal consistency reliability by Cronbach's α (CA). A subset of 625 patient

SUBMITTER: Jorgensen JB 

PROVIDER: S-EPMC12730740 | biostudies-literature | 2025 Dec

REPOSITORIES: biostudies-literature