Joint trajectories of disease activity, and physical and mental health-related quality of life in an inception lupus cohort.

OBJECTIVES

To examine for latent patterns of SLE disease activity trajectories that associate with specific latent patterns of health-related quality of life (HRQoL; Medical Outcomes Study Short Form-36), and to determine baseline predictors of class membership.

METHODS

In this retrospective longitudinal inception cohort of 222 SLE adults over 10 years, trajectories of three outcomes were studied jointly: Short Form-36 physical (PCS) and mental (MCS) component summaries and adjusted mean SLEDAI-2000 (AMS). Group-based joint trajectory modelling was used to model latent classes; univariable and multivariable analyses were used to identify predictors of class membership.

RESULTS

Four latent classes were identified: Class 1 (C1) (24%) had moderate AMS, and persistently low PCS and MCS; C2 (26%) had low AMS, moderate PCS and improved then worsened MCS; C3 (38%) had moderate AMS, and persistently high PCS and MCS; and C4 (11%) had high AMS, moderate-low PCS and improving MCS. Baseline older age was associated with lower HRQoL trajectories. Higher AMS trajectories did not associate with a particular pattern of HRQoL trajectory. A higher prevalence of fibromyalgia (44% in C1) was associated with worse HRQoL trajectories. Disease manifestations, organ damage and cumulative glucocorticoid were not differentially distributed across the latent classes.

CONCLUSION

High disease activity did not necessarily associate with low HRQoL. More patients with worse HRQoL trajectories had fibromyalgia. Older age at diagnosis increased the probability of belonging to a class with low HRQoL trajectories. The care of SLE patients may be improved through addressing fibromyalgia in addition to disease activity.