Cardiovascular Autonomic Dysfunction Across Rheumatoid Arthritis Disease Activity: Assessment Using Autonomic Reflex Tests, Heart Rate Variability, and COMPASS-31
Background: Rheumatoid arthritis (RA) is associated with increased cardiovascular morbidity, and autonomic nervous system dysfunction may contribute to this risk. The relationship between autonomic abnormalities and RA disease activity, however, remains incompletely defined. Objectives: To assess cardiovascular autonomic function in patients with RA using autonomic reflex tests, heart rate variability (HRV), and the Composite Autonomic Symptom Score-31 (COMPASS-31), and to examine differences across disease activity categories. Methods: This cross-sectional analysis included the 93 patients with RA enrolled in a study at AIIMS Bhopal. Cardiovascular autonomic reflex testing, five-minute resting HRV, and COMPASS-31 were assessed at baseline. Disease activity was categorised using the Clinical Disease Activity Index (CDAI). Continuous outcomes were compared using the Kruskal-Wallis test. Categorical autonomic-test classifications were compared using Pearson chi-square testing, with an exact test used when expected cell counts were small. Post-hoc pairwise comparisons were adjusted for multiple testing. Results: The mean age was 47.8 ± 11.0 years and 83.9% of participants were female. Low, moderate, and high disease activity were present in 16.1%, 55.9%, and 28.0%, respectively. The continuous 30:15 ratio differed across disease activity groups (P = 0.042), although no pairwise comparison remained significant after Holm adjustment. For categorical autonomic-test classifications, the 30:15 ratio (P = 0.040) and Valsalva response (P < 0.001) differed significantly across disease activity groups; the Valsalva difference was driven primarily by the moderate-versus-high comparison. Orthostatic hypotension did not reach significance when analysed using an exact test (P = 0.051). HRV parameters and COMPASS-31 scores did not differ significantly across disease activity groups. Conclusion: Abnormal cardiovascular autonomic reflex responses were frequent within this RA cohort, particularly for parasympathetic tests. Selected reflex-test measures differed by disease activity, whereas resting HRV and COMPASS-31 did not. The non-linear and method-dependent pattern suggests that autonomic involvement in RA is complex and is not uniformly captured by a single assessment modality.