Correlation of Sympathovagal Imbalance with Disease Activity and Inflammatory Markers in South Indian Patients with Rheumatoid Arthritis

Abstract

Background and Aim: Rheumatoid arthritis (RA) patients have higher risk of cardiovascular disease and mortality and that is not linked to traditional cardiovascular risk factors. Altered sympathovagal balance is associated with cardiovascular disease. In RA sympathovagal balance and inflammatory markers were reported to be increased, but there is inadequacy of data on its assessment and association with disease activity. This study was conducted to find the correlation of sympathovagal balance with disease activity and inflammatory markers in South Indian patients with RA. Methods: RA patients (diagnosis of RA made as per 2010 ACR/EULAR classification criteria) were enrolled from Department of Clinical Immunology, JIPMER. Participants were sub grouped as low disease activity (LDA), moderate disease activity (MDA) and severe disease activity (HDA) using disease activity score 28 with ESR. Frequency and time domain parameters of heart rate variability and inflammatory markers like Interleukin-1α (IL-1α), Interleukin-6 (IL-6), tumor necrosis factor-α (TNFα) and cortisol were measured for all the participants. Results: A total of 143 RA patients (23 in LDA group, 69 in MDA group and 51 in HDA group) were assessed during the study. LF-HF ratio (ratio of low frequency power to high frequency power) a marker of sympathovagal balance showed significant increase in MDA and HDA group compared to LDA group. LF-HF ratio correlated positively with DAS28 (r=0.473, p<0.001), cortisol (r=0.363, p<0.001), IL-1α (r=0.379, p<0.05). Conclusion: Sympathovagal imbalance was significantly increased in the MDA and HDA group compared to LDA group and positively correlated with disease activity, IL-1α and cortisol in the patients of RA. Assessment of sympathovagal balance may help to find the autonomic dysfunction and cardiovascular risk in RA.