Autonomic dysfunction in systemic lupus erythematosus and systemic sclerosis

Background and Objective Autonomic dysfunction may arise in chronic systemic diseases, including autoimmune connective tissue disorders. This study aimed to quantify autonomic symptom burden in patients with systemic lupus erythematosus (SLE) and systemic sclerosis (SSc), examine clinical correlates, and compare results with controls without autoimmune disease. Methods This cross-sectional study included 50 SLE patients, 50 SSc patients, and 35 controls. Clinical and demographic characteristics were collected during visits. Autonomic symptom burden was assessed using the Composite Autonomic Symptom Score-31 (COMPASS-31). COMPASS-31 total and subdomain scores were examined across groups and within disease groups according to clinical and serological variables. A post-hoc COMPASS-31 score >32.5 was used to define high autonomic symptom burden. Results Median total COMPASS-31 scores differed across groups and were higher in both SLE and SSc than in controls (15.43 and 20.53 vs 9.03; p = 0.001). Compared with SLE, SSc had higher orthostatic and vasomotor symptom burden. Using COMPASS-31 > 32.5, high autonomic symptom burden was present in 7/50 (14%) SLE and 13/50 (26%) SSc patients, while none of the controls exceeded the cut-off. In multivariable models, serositis and joint involvement predicted high symptom burden in SLE, whereas clinically significant gastrointestinal involvement and musculoskeletal involvement were independent predictors in SSc. After adjustment for age, sex, and comorbidity, total COMPASS-31 remained higher than in controls in both SLE (β = 7.01; p = 0.013) and SSc (β = 11.24; p < 0.001). Conclusion Autonomic symptom burden appears to be higher in patients with SLE and SSc than in controls. The subgroup differences suggest that autonomic symptoms may cluster with specific organ involvement. COMPASS-31 may be a practical screening tool to identify patients who could benefit from further objective autonomic evaluation. Routine, structured assessment may support timely recognition and management of autonomic symptoms in clinical practice.