September 13, 2017Open Access
Cardiovascular autonomic regulation, inflammation and pain in rheumatoid arthritis
Structured PICO
Is lower heart rate variability associated with systemic inflammation, pain, and compounded by hypertension in patients with rheumatoid arthritis?
P
Population
63 participants including rheumatoid arthritis (RA) patients who are normotensive (n=13) or hypertensive (n=17), and controls who are normotensive (n=17) or hypertensive (n=16)
C
Comparator
Normotensive controls and hypertensive controls
O
Outcome
Heart rate variability (time and frequency domain measures) and its association with serological markers of inflammation and reported painsurrogate
Lower heart rate variability in rheumatoid arthritis is independently associated with increased inflammation and pain, but is not further compounded by the presence of hypertension.
Abstract
BACKGROUND: Rheumatoid arthritis (RA) is a chronic inflammatory condition characterised by reduced heart rate variability (HRV) of unknown cause. We tested the hypothesis that low HRV, indicative of cardiac autonomic cardiovascular dysfunction, was associated with systemic inflammation and pain. Given the high prevalence of hypertension (HTN) in RA, a condition itself associated with low HRV, we also assessed whether the presence of hypertension further reduced HRV in RA. METHODS: In RA-normotensive (n=13), RA-HTN (n=17), normotensive controls (NC; n=17) and HTN (n=16) controls, blood pressure and heart rate were recorded. Time and frequency domain measures of HRV along with serological markers of inflammation (high sensitivity C-reactive protein hs-CRP, tumour necrosis factor-α TNF-α and interleukins IL) were determined. Reported pain was assessed using a visual analogue scale. RESULTS: Time (rMSSD, pNN50%) and frequency (high frequency power, low frequency power, total power) domain measures of HRV were lower in the RA, RA-HTN and HTN groups, compared to NC (p=0.001). However, no significant differences in HRV were noted between the RA, RA-HTN and HTN groups. Inverse associations were found between time and frequency measures of HRV and inflammatory cytokines (IL-6 and IL-10), but were not independent after multivariable analysis. hs-CRP and pain were independently and inversely associated with time domain (rMMSD, pNN50%) parameters of HRV. CONCLUSIONS: These findings suggest that lower HRV is associated with increased inflammation and independently associated with increased reported pain, but not compounded by the presence of HTN in patients with RA.