# Disease activity and mental health symptoms in axial spondyloarthritis: concordant or discordant?

## TL;DR

This study found that disease activity and mental health symptoms in axial spondyloarthritis patients are closely linked, with improvements in one often matching improvements in the other.

## Contribution

The study used latent class and trajectory modeling to test for subgroups with discordant disease and mental health scores in axSpA patients, finding none.

## Key findings

- Three baseline groups showed concordant disease activity and mental health scores, with the highest group having more joint involvement and higher CRP.
- Trajectory analysis revealed four groups with aligned mental health and disease activity changes over six months.
- High mental health symptom groups showed significant improvement in both domains following treatment.

## Abstract

We applied latent class and trajectory modelling to examine whether subgroups of axial spondylarthritis (axSpA) patients report discordant scores for disease activity and mental health symptoms at baseline and after treatment change.

We analysed axSpA patients from the ASAS Health Index International Validation Study. We applied latent class analysis (LCA) using generalized structural equation modelling to identify subgroups among 1292 individuals, based on baseline Hospital Anxiety and Depression Scale (HADS) subscores and ASDAS. We applied trajectory modelling in a subset (n = 206) requiring treatment change, to identify subgroups of distinct trajectories for HADS and ASDAS over 6 months. All indices were standardized. Baseline characteristics were compared across identified groups.

For the baseline analysis, three groups were identified with concordant HADS subscores and ASDAS, with similar baseline characteristics except the high HADS/ASDAS group having more peripheral joint involvement and higher CRP levels. Trajectory analysis identified four groups with concordant HADS and ASDAS changes: 54% comparatively low baseline values, 33% medium and, of the high baseline groups, some (7%) had marked improvement (HADS-depression Δ11, HADS-anxiety Δ9, ASDAS Δ2.8), while others (6%) had limited ASDAS improvement (Δ1.4) with minimal changes in anxiety symptoms (Δ0.6).

We did not identify the hypothesized subgroups with discordant disease activity and mental health symptoms. Instead, these domains were closely aligned at baseline and following treatment, suggesting that these symptoms influence each other. Patients with high mental health symptom burden may benefit from knowing that these symptoms often improve alongside disease activity when starting treatment.