Longitudinal trajectories of the Scleroderma Health Assessment Questionnaire (SHAQ) visual analogue scales: a retrospective cohort study

Objective: Systemic sclerosis (SSc) is disabling. However, the different factors contributing to this disability and how these change over time have been little studied. Our aim was to examine the trajectories over time of the six visual analogue scales (VAS) of the scleroderma HAQ (SHAQ), associations of disease-related factors with these trajectories, and relationships with overall functional ability.

Methods: This was a retrospective study of data collected prospectively from patients attending a single tertiary centre between 2005 and 2022. VAS (pain, intestinal, breathing, Raynaud's [RP], digital ulcers, 'overall') were analysed using linear mixed-effects models, and relationships between the six VAS and functional ability (HAQ-DI) and scleroderma functional index [FI] by correlating the average gradients obtained from individual linear regressions.

Results: 537 patients with at least two time-points were included, followed for a mean (SD) of 6.8 (4.2) years. VAS intestinal scores increased (ie worsened) by 0.085 points (95% CI = 0.041-0.130,p<0.001) per year, VAS breathing by 0.056 points (95% CI = 0.016-0.096,p=0.006) and VAS overall scores by 0.073 points (95% CI = 0.032-0.114,p=0.001). The longer the duration between RP onset and SSc diagnosis, the lower the VAS pain and VAS intestinal scores. The odds of having at least one digital ulcer reduced with disease duration, with diffuse cutaneous subtype and with anti-Scl70 positivity. Average gradients for all six VAS scales correlated (albeit variably/weakly) with HAQ-DI and scleroderma FI gradients.

Conclusion: Longitudinal assessment of the six SHAQ VAS, and associations of baseline characteristics with the individual VAS time courses, provide insights into disease trajectory and overall disability.