Fatigue in patients with coronary artery disease: association with thyroid axis hormones and cortisol

Causal association between self-reported fatigue and coronary artery disease: a bidirectional two-sample Mendelian randomization analysis

Background

Observational studies have reported the association between fatigue and coronary artery disease (CAD), but the causal association between fatigue and CAD is unclear.

Method

We conducted a bidirectional Mendelian randomization (MR) study using publicly available genome-wide association studies (GWAS) data. The inverse-variance weighted (IVW) method was used as the primary analysis. We performed three complementary methods, including weighted median, MR-Egger regression, and MR pleiotropy residual sum and outlier (MR-PRESSO) to evaluate the sensitivity and horizontal pleiotropy of the results.

Result

Self-reported fatigue had a causal effect on coronary artery atherosclerosis (CAA) (OR 1.047, 95%CI 1.033-1.062), myocardial infarction (MI) (OR 1.027 95%CI 1.014-1.039) and coronary heart disease (CHD) (OR 1.037, 95%CI 1.021-1.053). We did not find a significant reverse causality between self-reported fatigue and CAD. Given the heterogeneity revealed by MR-Egger regression, we employed the IVW random effect model. For the examination of fatigue on CHD and the reverse analysis of CAA, and MI on fatigue, the MR-PRESSO test found horizontal pleiotropy. No significant outliers were found.

Conclusion

The MR analysis reveals a causal relationship between self-reported fatigue and CAD. The results should be interpreted with caution due to horizontal pleiotropy.

Testing of a health-related quality of life model in patients with heart failure: A cross-sectional, correlational study

Psychological symptoms, physical symptoms, and behavioral factors can affect health-related quality of life (HRQOL) through different pathways, but the relationships have not been fully tested in prior theoretical models. The purpose of this study was to examine direct and indirect relationships of demographic (age), biological/physiological (comorbidity), psychological (depressive symptoms), social (social support), physical (physical symptoms and functional status), and behavioral (dietary sodium adherence) factors to HRQOL. Data from 358 patients with heart failure were analyzed using structural equation modeling. There was a good model fit: Chi-square = 5.488, p = .241, RMSEA = .032, CFI = .998, TLI = .985, and SRMR = .018. Psychological symptoms, physical symptoms, and demographic factors were directly and indirectly associated, while behavioral and biological/physiological factors were indirectly associated with HRQOL through different pathways. Behavioral factors need to be included, and psychological factors and physical factors need to be separated in theoretical models of HRQOL.

A quantile regression approach to explain the relationship of Fatigue and Cortisol, Cytokine among Koreans with Hepatitis B

Fatigue is a major symptom among patients with Hepatitis B virus (HBV). However, the physiological mechanisms regarding mediate fatigue and the relationships between fatigue, cortisol and cytokines are unclear in patients with HBV. The purpose of this study was to examine the relationships between perceived fatigue, cortisol, and cytokines in Korean patients with HBV. The mean score for overall fatigue was moderate. In linear regression analyses, TNF-α was only significant as a predictor of fatigue. In quantile regression analyses, the cortisol level was significant in the 70^th, 80^th, 90^th quantiles in the cognitive/mood fatigue subdimension, which correspond to severe levels of fatigue. IL-6 levels were significant in 90^th quantile in overall fatigue and in the cognitive/mood fatigue subdimension. Cortisol, IL-6, and TNF- α were related to perceived fatigue in patients with HBV, particularly in the cognitive/mood dimension. This suggests that the fatigue patterns of patients with HBV are related to their mental and mood states and physical responses, such as cortisol and cytokine levels, are correlated with the nature of the fatigue. In the clinic, interventions to manage fatigue in patients with HBV should be developed based on the characteristics of the fatigue.

Exploring potential biomarkers associated with health-related quality of life in patients with coronary artery disease and heart failure

Objective:

There has been a lack of research examining associations between biomarkers and health-related quality of life (HRQoL) in patients with coronary artery disease and heart failure. In patients with coronary artery disease and heart failure, we aimed to explore potential associations between biomarkers of health such as serum levels of thyroid hormones, N-terminal pro-B-type natriuretic peptide (NT-pro-BNP), inflammatory biomarkers and HRQoL.

Methods:

In sum, 482 patients (75% male; mean age 58±10 years) with coronary artery disease and heart failure were evaluated for socio-demographic and clinical coronary artery disease risk factors. Blood samples were drawn to evaluate thyroid hormones, NT-pro-BNP, high-sensitivity C-reactive protein and interleukin-6 (IL-6). Additional data was collected on HRQoL (the Minnesota Living with Heart Failure Questionnaire), anxiety and depressive symptoms (Hospital Anxiety and Depression Scale), Type D personality (DS14 scale).

Results:

In multivariable models, lower levels of high-sensitivity C-reactive protein and interleukin-6 were associated with worse results on the Minnesota Living with Heart Failure Questionnaire emotional subscale (β = −0.107, p = 0.003; β = −0.106, p = 0.004). Lower levels of interleukin-6 were associated with worse perceived global health (β = −0.101, p = 0.011).

Conclusion:

Even after controlling for socio-demographic and clinical risk factors including mental distress symptoms, lower levels of inflammatory biomarkers were associated with worse HRQoL.

A Systematic Review of Biological Mechanisms of Fatigue in Chronic Illness

Fatigue, a commonly reported symptom, is defined as an overwhelming, debilitating, and sustained sense of exhaustion that decreases the ability to function and carry out daily activities. To date, cancer researchers have been in the forefront in investigating the possible biological mechanisms of fatigue, identifying inflammation, dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis, and activation of the autonomic nervous system. The purpose of this systematic review is to describe fatigue and what is known about the biological mechanisms described in cancer in five chronic, noninfectious illnesses: heart failure, multiple sclerosis, chronic kidney disease, rheumatoid arthritis, and chronic obstructive pulmonary disease. We searched PubMed and EMBASE using fatigue as a major Medical subject headings (MeSH) heading with each individual disease added as a search term followed by each biological mechanism. We included only primary research articles published in English between 1996 and 2016 describing studies conducted in adult humans. We identified 26 relevant articles. While there is some evidence that the biological mechanisms causing fatigue in cancer are also associated with fatigue in other chronic illnesses, more research is needed to explore inflammation, the HPA axis, and the autonomic nervous system, and other mechanisms in relation to fatigue in a variety of chronic illnesses.

Association of Exercise Capacity with Physical Functionality and Various Aspects of Fatigue in Patients with Coronary Artery Disease

The aim of this study was to examine associations between exercise capacity-indexed as the metabolic equivalent of the task-and various aspects of subjective fatigue, physical functionality, and depression in patients with coronary artery disease. A cross-sectional design was used. Patients with stable coronary artery disease (N = 240) underwent an exercise stress test and completed self-report assessments of depression, subjective physical limitations, vital exhaustion, and the impact of fatigue on physical, social, and cognitive functions. Associations between exercise capacity and these self-report variables were assessed using bivariate correlations and a series of multivariate regressions. Exercise capacity was negatively associated with vital exhaustion, physical limitations, and impact of fatigue on physical and social functioning but not on cognitive functioning. There was a marginal association between exercise capacity and depression. The associations between exercise capacity and fatigue remained significant even after controlling for effects of age, body mass index, gender, education, and comorbid diabetes mellitus. The main conclusion of the study is that in patients with coronary artery disease, exercise capacity has the strongest predictability for physical fatigue, but, importantly, it also independently predicts the feeling of loss of energy and malaise.

Low fT3 is associated with diminished health-related quality of life in patients with acute coronary syndrome treated with drug-eluting stent: a longitudinal observational study

Acute coronary syndrome (ACS) patients with low triiodothyronine (T3) syndrome characterized by low free T3 (fT3) levels with normal thyroxine (T4) and thyroid-stimulating hormone (TSH) have a higher rate of death. The impact of fT3 on Health related quality of life (HRQOL) in patients with ACS is still unknown. 528 ACS patients treated with drug-eluting stent (DES) were included in this prospective, observational study. Patients were classified into low fT3 group (n=126) and normal fT3 group (n=402) according to serum fT3 level. Every patient was prospectively interviewed at baseline and 1 year following percutaneous coronary intervention (PCI). HRQOL was assessed with the use of the Medical Outcomes Study 36-Item Short-Form Health Survey (SF-36). Low fT3 patients had poorer HRQOL than normal fT3 patients both at baseline and 1-year follow-up (all p<0.05). During 1-year follow-up, HRQOL scores for all patients were significantly higher than baseline. Low fT3 patients had lesser gains in physical functioning, bodily pain, general health, vitality, social functioning and role emotional (all p<0.05). Generally, low fT3 patients demonstrated less improvement in Physical Component Score (PCS) (p=0.008) and Mental Component Score (MCS) (p=0.001). The percentage of patients reaching MCID for PCS and MCS was lower in low fT3 group than that in normal fT3 group (p<0.001). Multivariate linear regression analyses showed that low level of fT3 was an independent risk factor for PCS and MCS improvements. In conclusion, a low fT3 level is a predictor of worse HRQOL improvement in ACS patients treated with DES.

Plasma leptin concentration is associated with fatigue severity in patients with cardiovascular risk factors - HSCAA study

Fatigue induced by complex dysfunctions of the central nervous system is frequently complained by patients with cardiovascular risk factors. Although leptin is considered to regulate the central nervous system, there are no reports regarding its association with fatigue in those patients. This cross-sectional study included 347 patients with cardiovascular risk factors. Fatigue score and plasma leptin concentration were measured. In addition, abdominal fat accumulation, systemic inflammation, sleep condition, and functions of hypothalamus-pituitary axis and autonomic system were estimated. Plasma leptin concentration (natural logarithm transformed) was significantly and positively (r=0.222, p<0.001) associated with fatigue score, and significantly (p<0.001) higher in the moderately-fatigued group (2.32±0.75ng/ml, mean±SD, n=52) than in the normally-fatigued group (1.85±1.02ng/ml, mean±SD, n=295). Multiple logistic regression analysis showed that plasma leptin concentration was significantly and independently associated with a moderately-fatigued condition independent of other factors, including age, gender, presence of diabetes, hypertension, dyslipidemia, alcohol consumption habit, urinary free cortisol, serum high-sensitive CRP concentration, visceral and subcutaneous fat area, apnea/hypopnea index, sleep efficiency, and heart rate variability. Hyperleptinemia may contribute to fatigue severity in patients with cardiovascular risk factors.

Early and Short-term Triiodothyronine Supplementation Prevents Adverse Postischemic Cardiac Remodeling: Role of Transforming Growth Factor-β1 and Antifibrotic miRNA Signaling

Activation of transforming growth factor (TGF)-β1 signaling in the ischemia/reperfusion (I/R) injured myocardium leads to dysregulation of miR-29-30-133, favoring the profibrotic process that leads to adverse cardiac remodeling (CR). We have previously shown that timely correction of the postischemic low-T3 syndrome (Low-T3S) exerts antifibrotic effects, but the underlying molecular players are still unknown. Here we hypothesize that a prompt, short-term infusion of T3 in a rat model of post I/R Low-T3S could hamper the early activation of the TGFβ1-dependent profibrotic cascade to confer long-lasting cardioprotection against adverse CR. Twenty-four hours after I/R, rats that developed the Low-T3S were randomly assigned to receive a 48-h infusion of 6 μg/kg/d T3 (I/R-L+T3) or saline (I/R-L) and sacrificed at 3 or 14 d post-I/R. Three days post-I/R, Low-T3S correction favored functional cardiac recovery. This effect was paralleled by a drop in TGFβ1 and increased miR-133a, miR-30c and miR-29c in the infarcted myocardium. Consistently, connective transforming growth factor (CTGF) and matrix metalloproteinase-2(MMP-2), validated targets of the above miRNAs, were significantly reduced. Fourteen days post-I/R, the I/R-L+T3 rats presented a significant reduction of scar size with a better preservation of cardiac performance and LV chamber geometry. At this time, TGFβ1 and miR-29c levels were in the normal range in both groups, whereas miR-30c-133a, MMP-2 and CTGF remained significantly altered in the I/R group. In conclusion, the antifibrotic effect exerted by T3 in the early phase of postischemic wound healing triggers a persistent cardioprotective response that hampers the progression of heart dysfunction and adverse CR.

Diurnal Cortisol Rhythm Is Associated With Adverse Cardiac Events and Mortality in Coronary Artery Bypass Patients

PURPOSE

There is growing evidence that the hypothalamic-pituitary-adrenal axis plays a role in the progression of cardiovascular disease. We examined the relationship between diurnal cortisol rhythm and adverse events in patients undergoing coronary artery bypass graft (CABG) surgery. We hypothesized that a flatter presurgical diurnal cortisol slope would be associated with higher rates of adverse cardiac events and death in the years following the CABG procedure.

METHODS

Repeated measures of saliva were taken over the day from 250 CABG patients 1 month before surgery to assess diurnal cortisol slope and overall output (area under the curve). Long-term clinical outcomes were occurrence of a major adverse cardiac event (MACE) and death, and were collected up to 2.68 (SD = 0.40) years after surgery. Cox proportional hazard models were used to determine relationships between presurgical cortisol and clinical outcomes. EuroSCORE, chronic illness burden, and whether or not the patient had undergone cardiopulmonary bypass were included as covariates in the models.

RESULTS

Diurnal cortisol slope predicted the occurrence of MACE or death after surgery (hazard ratio = 0.73; 95% confidence interval = 0.56-0.96; P = .023). Patients with a steeper slope were at reduced risk of adverse outcomes. This association was driven by changes in both waking and evening cortisol levels.

CONCLUSION

These results provide evidence for a link between diurnal cortisol rhythm and recovery after CABG. Measuring diurnal cortisol slope before surgery may help to identify those patients at risk of adverse outcomes in the years after the procedure.

Decreased physical effort, fatigue, and mental distress in patients with coronary artery disease: importance of personality-related differences

BACKGROUND

Identification of cardio-toxic psychological symptoms in coronary artery disease (CAD) patients is important.

PURPOSE

We examined the association of negative affectivity (NA), social inhibition (SI), and their combination in the distressed (Type D) personality with functional status, fatigue, and mental distress in CAD patients.

METHOD

Following acute coronary syndrome, 690 consecutive CAD patients agreed to participate in this cross-sectional study and were evaluated for clinical characteristics, including left ventricular ejection fraction (LVEF), and for NA, SI, and Type D personality (i.e., NA and SI; DS14 scale) when they entered a cardiac rehabilitation program in Lithuania. Patient-centered outcomes included functional status (bicycle ergometer), symptoms of fatigue (Multidimensional Fatigue Inventory-20), and mental distress (Beck Depression Inventory-II and Hospital Anxiety and Depression Scale).

RESULTS

The reference subgroup (neither NA nor SI) included 34 % of patients; 13 % had NA only, 19 % had SI only, and 34 % had Type D profile. Type D patients had worse functional status, and Type D patients and NA-only patients had higher symptom levels of fatigue and mental distress. In multivariate regression models that included LVEF, clinical characteristics, and depressive symptoms, Type D personality was an independent predictor of decreased exercise capacity (OR = 1.77, 95 % CI 1.06-2.95, p = .03) and decreased motivation for activity (OR = 3.14, 95 % CI 1.73-5.73, p < .001). Type D, NA, and SI were also independent predictors of mental distress.

CONCLUSIONS

Type D personality traits independently predicted poor functional status and worse patient-centered outcomes independently from LVEF and depression. Further studies exploring personality-related differences in cardiovascular outcomes are needed.

Voluntary exercise adapts the hypothalamus-pituitary-thyroid axis in male rats

The hypothalamic-pituitary thyroid (HPT) axis modulates energy homeostasis. Its activity decreases in conditions of negative energy balance but the effects of chronic exercise on the axis are controversial and unknown at hypothalamic level. Wistar male rats were exposed for up to 14 days to voluntary wheel running (WR), or pair-feeding (PF; 18% food restriction), or to repeated restraint (RR), a mild stressor. WR and RR diminished food intake; body weight gain decreased in the 3 experimental groups, but WAT mass and serum leptin more intensely in the WR group. WR, but not RR, produced a delayed inhibition of central markers of HPT axis activity. At day 14, in WR rats paraventricular nucleus-pro-TRH mRNA and serum TSH levels decreased, anterior pituitary TRH-receptor 1 mRNA levels increased, but serum thyroid hormone levels were unaltered, which is consistent with decreased secretion of TRH and clearance of thyroid hormones. A similar pattern was observed if WR animals were euthanized during their activity phase. In contrast, in PF animals the profound drop of HPT axis activity included decreased serum T3 levels and hepatic deiodinase 1 activity; these changes were correlated with an intense increase in serum corticosterone levels. WR effects on HPT axis were not associated with changes in the activity of the hypothalamic-pituitary adrenal axis, but correlated positively with serum leptin levels. These data demonstrate that voluntary WR adapts the status of the HPT axis, through pathways that are distinct from those observed during food restriction or repeated stress.

Ischemic stroke functional outcomes are independently associated with C-reactive protein concentrations and cognitive outcomes with triiodothyronine concentrations: a pilot study

Elevated concentrations of C-reactive protein (CRP) and decreased concentrations of triiodothyronine (T3) were shown to predict poor outcomes in patients with stroke. However, the prognostic value of CRP and T3 has not been studied simultaneously in relation to stroke functional and cognitive outcomes despite of close interaction between inflammatory markers and thyroid function. We evaluated the association of thyroid hormone and CRP concentrations with immediate outcomes after ischemic stroke. Eighty-eight ischemic stroke patients on admission to the stroke unit were evaluated for clinical stroke severity (Scandinavian stroke scale or SSS) and concentrations of thyroid-stimulating hormone, free thyroxin, free T3, and CRP. Functional outcome (modified Rankin scale) and cognitive outcome (Mini mental state examination) were evaluated at discharge. Greater ln CRP concentrations (r = -0.35, p = 0.001), but not thyroid hormone concentrations, correlated with score on the SSS. In univariate analyses lower free T3 concentrations and higher CRP concentrations were associated with poor functional and poor cognitive outcomes. After adjustment for clinical stroke severity, higher CRP concentrations (β = 0.18, p = 0.04) remained associated with worse functional outcome and lower free T3 concentrations with worse cognitive outcome (β = 0.23, p = 0.03). In sum, clinical stroke severity is associated with elevated CRP concentration. Higher CRP concentration is independently associated with worse functional outcomes and lower free T3 concentration with worse cognitive outcomes at discharge. T3 and CRP can be important biomarkers in patients with acute ischemic stroke.

Relationship of health-related quality of life with fatigue and exercise capacity in patients with coronary artery disease

OBJECTIVE

The study objective was to evaluate the relationship of health-related quality of life (HRQoL) with fatigue and exercise capacity in coronary artery disease (CAD) patients.

METHODS

A total of 1072 consecutive CAD patients on admission to a cardiac rehabilitation program were evaluated for HRQoL (36-item Short Form Medical Outcome Questionnaire; SF-36), body mass index, clinical characteristics (New York Heart Association (NYHA) class, angina pectoris class, coronary interventions, treatment with beta blockers, hypertension and diabetes), symptoms of depression and anxiety (Hospital Anxiety and Depression Scale), fatigue (Multidimensional Fatigue Inventory-20; MFI-20), and exercise capacity (bicycle ergometer test).

RESULTS

In univariate regression analyses lower scores on all SF-36 domains were associated with greater scores on all MFI-20 subscales. Exercise capacity was associated with all SF-36 domains, except for social functioning and mental health domains. In multivariate regression analyses, after adjusting for age, gender, body mass index, NYHA class, angina pectoris class, hypertension, diabetes, coronary interventions, treatment with betablockers, and symptoms of depression and anxiety, greater limitation due to physical and due to emotional problems, poor social functioning, decreased energy/vitality, worse general health perception, reduced mental component summary and lower global SF-36 score were independently associated with higher MFI-20 general fatigue score. Reduced physical functioning, greater pain, and reduced physical component summary SF-36 scores were associated with greater MFI-20 physical fatigue score. Lower SF-36 mental health score was associated, with greater MFI-20 mental fatigue score.

CONCLUSION

In CAD patients undergoing rehabilitation, poor HRQoL is associated with greater fatigue and decreased exercise capacity independently from mental distress and CAD severity score.