Background While SLE patients have poorer health-related quality of life (HRQoL) and more severe anxiety symptoms than healthy individuals, the impact of inflammation on mood symptoms and declined HRQoL is unknown.
Objectives To compare the severity of and explore the correlations between mood symptoms, HRQoL and serum pro-inflammatory cytokine levels in SLE patients and healthy controls.
Methods Consecutive patients who satisfied the ACR classification criteria for SLE and healthy subjects matched for age and sex were recruited for this study. For all the participants, the severity of anxiety and depressive symptoms, pain and HRQoL were assessed by the hospital anxiety and depression scale (HADS), the visual analogue scale (VAS) and the Short Form Health Survey-36 (SF-36) respectively. SLE disease activity was evaluated by the SLE Disease Activity Index (SLEDAI-2K). A panel of serum pro-inflammatory cytokines comprising interleukin (IL)-1β, IL-6, IL-17, IL-23, IL-33 and tumour necrosis factor (TNF)α was determined by the multiplex enzyme-linked immunosorbant assay (Millipore®). The differences in mood symptoms, SF-36 and its components, and pro-inflammatory cytokine levels were compared by student t-test between the 2 groups. The correlations between mood symptoms, SF-36 and pro-inflammatory cytokines were explored by bivariate Pearson’s correlation. Independent predictors for SF-36 and mood symptoms were explored with adjustment for age, pain, SLEDAI and daily glucocorticoid dose.
Results Fifty four SLE patients and 54 healthy controls were studied (89% female in each group). The mean (±SD) age of the patients and healthy controls were 40.02±13.7 and 40.59±14.8 years respectively (p=0.835). In the SLE group, the mean (±SD) SLEDAI and the daily prednisolone dose were 3.85±3.8 (range 0-16) and 10.44±12.1mg (range 0-40) respectively. Both the mean (±SD) anxiety and depression scores in SLE group were significantly higher than that of the healthy controls (5.65±4.1 vs 3.74±2.9, p=0.006 and 3.87±3.0 vs 2.33±2.3, p=0.003, respectively). The mean (±SD) scores of SF-36 and its physical (PC) and mental (MC) components in SLE group were significantly lower than that of the healthy subjects (SF-36=67.87±19.8 vs 84.54±8.7, p<0.001; PC=66.98±19.1 vs 82.37±9.8, p<0.001; MC=64.46±20.0 vs 80.15±11.2, p<0.001). SLE patients had a significantly higher level of TNFα than that of the healthy controls (17.24±13.92 vs 8.64±5.43 pg/ml, p<0.001). Amongst the SLE patients, correlation analysis revealed significant negative correlations between the serum level of IL-17 and the MC and PC of SF-36 (r=-0.305, p=0.025; r=-0.409, p=0.002, respectively) while serum TNFα was negatively correlated with the MC of SF-36 (r=-0.316, p=0.020). After adjustment for age, VAS pain score, SLEDAI and daily glucocorticoid dose, only serum IL-17 level was significantly associated with the PC (beta=-0.374, p=0.025) and MC of SF-36 in SLE patients (beta=-0.386, p=0.002). No significant relationship was found between proinflammatory cytokine levels and HADS in SLE patients. In healthy controls, no significant relationships were found between proinflammatory cytokine levels, HADS and HRQoL.
Conclusions IL-17 appears to correlate with poorer HRQoL in SLE patients. Further studies are imperative to address the potential immunopathological basis of the impact of IL-17 on HRQoL in SLE.
Disclosure of Interest None Declared