Background Rheumatoid arthritis (RA) is an autoimmune chronic inflammatory disease associated with cardiovascular autonomic neuropathy. Cardiovascular autonomic neuropathy is a significant risk predictor for sudden cardiac death in rheumatoid arthritis.1 Sudomotor dysfunction reflects small fibre neuropathy, cardiovascular autonomic neuropathy and peripheral sympathetic autonomic neuropathy.2 However, sudomotor dysfunction and its relationship with inflammatory measures remain unexplored in RA patients in the absence of traditional cardiovascular (CV) risk factors.
Objectives The aim of present study was to assess the sudomotor function and its association with disease specific measures: ESR, CRP and DAS-28 in RA patients with no apparent conventional cardiovascular risk factor.
Methods In this cross-sectional study, 60 RA patients fulfilling 2010 Rheumatoid Arthritis Classification Criteria3 and 40 age and sex-matched healthy controls were recruited. Sudomotor function was assessed using Sudoscan (Impeto Medical, Paris, France) through measurement of electrochemical skin conductance of hands and feet.2 Sudoscan investigates the sweat gland activity and used as a surrogate to study the damage of sympathetic sudomotor nerves in neuropathy. It is an indirect assessment tool of sudomotor function. Inflammatory measures such as ESR and CRP and DAS-28 (disease activity score in 28 joints) were determined.
Results Rheumatoid arthritis patients had significantly impaired sudomotor function (56.90±12.95 vs. 76.15±8.45 μs, p<0.00, Figure 1A), elevated ESR (31.30±12.34 vs. 16.72±4.46, p<0.001) and CRP (10.55±3.81 vs. 3.81±1.03, p=0.002) as compared to healthy controls, respectively. The mean disease duration of RA patients was 9.15±5.76 and they had high disease activity (mean DAS-28, 4.60±1.72). Sudomotor function was found to be inversely correlated with ESR (r =0.42, p=0.001, Figure 1B), CRP (r =0.60, p<0.001, Figure 1C) and DAS-28 (r =0.38, p=0.003, Figure 1D).
Conclusions Cardiovascular autonomic neuropathy occurs in RA in the absence of traditional CV risk factors. Sudomotor dysfunction is significantly associated with increased level of ESR, CRP and disease activity suggesting that increased inflammation may cause sudomotor dysfunction.
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Disclosure of Interest None declared