Prospective associations between illness perceptions and health outcomes in patients with systemic sclerosis and systemic lupus erythematosus: a cross-lagged analysis

OBJECTIVE: Perceptions of patients with SLE and SSc are strongly associated with physical and psychological outcomes. This interplay is not yet fully understood. Therefore, the aim of this study was to explore the prospective associations between illness perceptions and depressive symptoms, anxiety, perceived health status and disease activity in SLE and SSc patients. METHODS: Patients with SLE and SSc from a single-centre university hospital participated in a longitudinal study spanning 1 year. At both time points, participants completed the revised Illness Perception Questionnaire; Hospital Anxiety and Depression Scale for measuring depressive symptoms and anxiety; The EuroQol five-dimensions with 5 response levels for perceived health status; and disease activity was recorded. The directionality of the associations was investigated using cross-lagged path analysis. RESULTS: A total of 128 SLE and 113 SSc patients with a mean (s.d.) age of 46.28 (14.97) and 60.17 (10.82) years, respectively, and mean (S.D.) disease duration of 13.90 (9.31) and 8.48 (9.14) years, respectively, participated. In SLE, more depressive symptoms, more anxiety and worse perceived health status predicted a relative decrease in illness coherence 1 year later. More severe perceived consequences predicted a relative decrease in perceived health status. The perception of a more chronic time course predicted an increase in depressive symptoms. In SSc, reporting more depressive symptoms and more anxiety predicted a relative decrease in illness coherence. A good perceived health status and less reporting of depressive symptoms predicted a relative decrease in perceived consequences. CONCLUSION: Evidence was obtained for reciprocal pathways between health outcomes and illness perceptions, although the predominant direction of effects was found to be from health outcomes to illness perceptions. TRIAL REGISTRATION: ClinicalTrials.gov, http://clinicaltrials.gov, NCT02655640.