Exploring the relationship between fatigue and circulating levels of the pro-inflammatory biomarkers interleukin-6 and C-reactive protein in the chronic stage of stroke recovery: A cross-sectional study

Abstract

BackgroundThe precise mechanisms underlying the aetiology of post-stroke fatigue remain poorly understood. Inflammation has been associated with clinically significant fatigue across a number of neurological disorders; however, at present there is a lack of evidence regarding the association of fatigue and inflammation in the chronic phase of stroke recovery. AimsThe aim of this study was to examine fatigue in a cohort of stroke survivors in the chronic phase of stroke, compared with matched controls, and to explore associations between the pro-inflammatory cytokine interleukin-6, high-sensitivity C-reactive Protein and fatigue. MethodsWe performed an exploratory cross-sectional study of 70 people in the chronic phase of stroke recovery, and 70 age matched controls. Fatigue was assessed using the Fatigue Assessment Scale. Interleukin-6 was measured in serum using a commercially available enzyme immunoassay kit. Both outcome measures were assessed contemporaneously. ResultsClinically significant fatigue, defined as a score ≥24 on the Fatigue Assessment Scale, was reported by 60% of stroke survivors, and 15.7% of controls. The odds of experiencing clinically significant fatigue was 8.04 times higher among stroke survivors compared to control participants (odds ratio 8.045; 95% CI: 3.608, 17.939; P ​< ​0.001). The fatigue score was significantly correlated with the level of both interleukin-6 and high-sensitivity c-reactive protein, however once entered into a linear regression model with cardiovascular covariables, this relationship was no longer statistically significant. ConclusionsThis study shows that fatigue may be associated with systemic inflammation in the chronic phase of stroke. The pathological mechanisms underlying post-stroke fatigue and its clinical implications require further study.