Fatigue in patients with chronic obstructive pulmonary disease: protocol of the Dutch multicentre, longitudinal, observational FAntasTIGUE study

COPD patient profiles in primary care. Referral criteria

COPD is a disease with a high prevalence that diminishes the quality of life of many patients. Despite this, there are still high rates of under-diagnosis in Spain, partly due to a lack of recognition of the pathology by patients. In this context, the role played by primary care teams becomes fundamental, as they are one of the first lines of entry into the health system. In this paper we explain the different COPD profiles that may be present, and update the tools for diagnosis and treatment, which, together with an attitude of active suspicion of the disease, can help in the correct management of patients, whether they are undiagnosed or have subsequent complications.

Analysing the Effects of Different Types of Exercise on Dyspnoea and Fatigue in Adults through COPD-Systematic Review and Meta-Analysis of Randomised Clinical Trials

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is a heterogeneous lung condition, the main symptoms of which are dyspnoea and fatigue. Though exercise has been recommended for subjects with COPD, its benefits remain unclear. The aim of this study was to summarise, through a systematic review and meta-analysis, the available evidence on the effects of aerobic, resistance, stretching, and combined exercise on the main symptoms of COPD.

METHODS

Search was performed using the electronic databases PubMed and Web of Science. Randomised controlled trials (RCTs) with interventions based on aerobic, resistance and/or combined exercise published until July 2022 were identified. The effects were summarised based on standardised mean differences (95% confidence intervals) using random and fixed effect models.

RESULTS

Eight studies were selected, including a total of 375 subjects. The results obtained showed that resistance exercise, aerobic exercise and combined exercise seem to improve dyspnoea and fatigue symptoms in COPD subjects.

CONCLUSIONS

In general, we can conclude that exercise-based interventions appear to improve the main COPD symptoms and may benefit quality of life in this population.

Relationship among Body Composition, Adipocytokines, and Irisin on Exercise Capacity and Quality of Life in COPD: A Pilot Study

Adipose tissue is an endocrine organ that interferes with the severity of chronic obstructive pulmonary disease (COPD). Although inflammatory markers, body composition, and nutritional status have a significant impact on pulmonary function, the real contribution of adipocytokines and myokines in COPD is still controversial. We aimed to evaluate the role played by the body composition, leptin, adiponectin, haptoglobin, and irisin on the functional exercise capacity, respiratory function, and quality of life (QoL) in COPD. In 25 COPD (20% GOLD-1; 60% GOLD-2; 20% GOLD-3) patients and 26 matched control subjects, we find that leptin, total adiponectin and haptoglobin are significantly increased whereas the 6 min walk test (6MWT) and physical functioning scores are significantly decreased in COPD versus controls. A significant positive relationship is found between leptin and fat mass and between 6MWT and the good health indicators of nutritional status. A significant inverse relationship is found between 6MWT and leptin and fat mass, FEV₁ and haptoglobin, and irisin and haptoglobin. Phase angle and leptin level are significant predictors for functional exercise capacity assessed with 6MWT. Taken altogether, the results of this pilot study further support the role played by body composition and adipocytokines on exercise capacity respiratory function and QoL in COPD.

Amino Acid Homeostasis and Fatigue in Chronic Hemodialysis Patients

Patients dependent on chronic hemodialysis treatment are prone to malnutrition, at least in part due to insufficient nutrient intake, metabolic derangements, and chronic inflammation. Losses of amino acids during hemodialysis may be an important additional contributor. In this study, we assessed changes in plasma amino acid concentrations during hemodialysis, quantified intradialytic amino acid losses, and investigated whether plasma amino acid concentrations and amino acid losses by hemodialysis and urinary excretion are associated with fatigue. The study included a total of 59 hemodialysis patients (65 ± 15 years, 63% male) and 33 healthy kidney donors as controls (54 ± 10 years, 45% male). Total plasma essential amino acid concentration before hemodialysis was lower in hemodialysis patients compared with controls (p = 0.006), while total non-essential amino acid concentration did not differ. Daily amino acid losses were 4.0 ± 1.3 g/24 h for hemodialysis patients and 0.6 ± 0.3 g/24 h for controls. Expressed as proportion of protein intake, daily amino acid losses of hemodialysis patients were 6.7 ± 2.4% of the total protein intake, compared to 0.7 ± 0.3% for controls (p < 0.001). Multivariable regression analyses demonstrated that hemodialysis efficacy (Kt/V) was the primary determinant of amino acid losses (Std. β = 0.51; p < 0.001). In logistic regression analyses, higher plasma proline concentrations were associated with higher odds of severe fatigue (OR (95% CI) per SD increment: 3.0 (1.3; 9.3); p = 0.03), while higher taurine concentrations were associated with lower odds of severe fatigue (OR (95% CI) per log2 increment: 0.3 (0.1; 0.7); p = 0.01). Similarly, higher daily taurine losses were also associated with lower odds of severe fatigue (OR (95% CI) per log2 increment: 0.64 (0.42; 0.93); p = 0.03). Lastly, a higher protein intake was associated with lower odds of severe fatigue (OR (95% CI) per SD increment: 0.2 (0.04; 0.5); p = 0.007). Future studies are warranted to investigate the mechanisms underlying these associations and investigate the potential of taurine supplementation.

Differences in Pulmonary and Extra-Pulmonary Traits between Women and Men with Chronic Obstructive Pulmonary Disease

Background: Evidence suggests sex-related differences in chronic obstructive pulmonary disease (COPD). Whether these differences are reflected in the prevalence of treatable traits remains unknown. Methods: Two samples of patients referred to secondary (n = 530) or tertiary care (n = 2012) were analyzed. Men and women were matched for age, forced expiratory volume in 1 s and body mass index. Sex-related differences were tested using t-tests, Mann-Whitney U, or chi-square tests. Results: Frequent exacerbations (30.5 vs. 19.7%), high cardiovascular risk (88.1 vs. 66.2%) and activity-related severe dyspnea (50.9 vs. 34.8%) were more prevalent in women in secondary care (p < 0.05). Severe hyperinflation (43.0 vs. 25.4%), limited diffusing capacity (79.6 vs. 70.1%), impaired mobility (44.0 vs. 28.7%), frequent exacerbations (66.8 vs. 57.4%), frequent hospitalizations (47.5 vs. 41.6%), severe activity-related dyspnea (89.1 vs. 85.0%), symptoms of anxiety (56.3 vs. 42.0%) and depression (50.3 vs. 44.8%), and poor health status (79.9 vs. 71.0%) were more prevalent in women in tertiary care (p < 0.05). Severe inspiratory muscle weakness (14.6 vs. 8.2%) and impaired exercise capacity (69.1 vs. 59.6%) were more prevalent among men (p < 0.05) in tertiary care. Conclusions: Sex-related differences were found, with most traits more prevalent and severe among women. Care providers should be aware of these differences to adjust treatment.

Feasibility of a Health Coaching and Home-Based Rehabilitation Intervention With Remote Monitoring for COPD

BACKGROUND

Pulmonary rehabilitation is an effective treatment for patients with COPD, but patient uptake and adherence to the current offering of center-based pulmonary rehabilitation is modest due to transportation, access, poverty, and frailty, and even more so in the context of the COVID pandemic. Home-based options have been proposed and were found noninferior to center-based rehabilitation; however, there is a lack of home-based programs, and more understanding is needed. We aimed to test the feasibility, uptake, and adherence to a home-based program for COPD rehabilitation with health coaching.

METHODS

We conducted a randomized trial with a wait-list controlled design to evaluate the effects of a home-based program with health coaching on breathlessness in subjects with moderate to severe COPD unable to attend the regular pulmonary rehabilitation program. The 8-week intervention consisted of video-guided exercises to be done 6 times a week and captured with a computer tablet. Health coaching was done weekly over the telephone to review subject activity and symptoms and to provide an opportunity for the subject to define their weekly goals. The primary outcomes were uptake, adherence, and Chronic Respiratory Questionnaire (CRQ) Dyspnea Domain. Secondary outcomes were self-management abilities and CRQ Emotions-Mastery-Fatigue.

RESULTS

154 subjects with moderate to severe COPD were randomized. Subject adherence was 86% to the proposed 6-times a week exercise routine. There (P = .062) was no significant difference in breathlessness (CRQ dyspnea). There was a significant improvement in self-management abilities (P < .001). The results of the qualitative interviews showed high levels of acceptability of the program.

CONCLUSIONS

The tested home-based rehabilitation program with health coaching was feasible, highly acceptable, showed a high degree of adherence, and improved self-management abilities. This study offers seminal information for home-based rehabilitation programs to design alternative options of rehabilitation to individuals with COPD that cannot attend to the well-established center-based pulmonary rehabilitation. (ClinicalTrials.gov registration NCT02557178.).

The prevalence and related factors of fatigue in patients with COPD: a systematic review

BACKGROUND

Fatigue is a distressing symptom in patients with COPD. Little is known about the factors that contribute to fatigue in COPD. This review summarises existing knowledge on the prevalence of fatigue, factors related to fatigue and the instruments most commonly used to assess fatigue in COPD.

METHODS

Pubmed, PsycINFO, EMBASE, Cochrane and CINAHL databases were searched for studies from inception up to 7 January 2020 using the medical subject headings "COPD" and "Fatigue". Studies were reviewed in accordance with PRISMA guidelines.

RESULTS

196 studies were evaluated. The prevalence of fatigue ranged from 17-95%. Age (r=-0.23 to r=0.27), sex (r=0.11), marital status (r=-0.096), dyspnoea (r=0.13 to r=0.78), forced expiatory volume in 1 s % predicted (r=-0.55 to r=-0.076), number of exacerbations (r=0.27 to r=0.38), number of comorbidities (r=0.10), number of medications (r=0.35), anxiety (r=0.36 to r=0.61), depression (r=0.41 to r=0.66), muscle strength (r=-0.78 to r=-0.45), functional capacity (r=-0.77 to r=-0.14) and quality of life (r=0.48 to r=0.77) showed significant associations with fatigue.

CONCLUSIONS

Fatigue is a prevalent symptom in patients with COPD. Multiple physical and psychological factors seem to be associated with fatigue. Future studies are needed to evaluate these underlying factors in integral analyses in samples of patients with COPD.

Creatine homeostasis and protein energy wasting in hemodialysis patients

Muscle wasting, low protein intake, hypoalbuminemia, low body mass, and chronic fatigue are prevalent in hemodialysis patients. Impaired creatine status may be an often overlooked, potential contributor to these symptoms. However, little is known about creatine homeostasis in hemodialysis patients. We aimed to elucidate creatine homeostasis in hemodialysis patients by assessing intradialytic plasma changes as well as intra- and interdialytic losses of arginine, guanidinoacetate, creatine and creatinine. Additionally, we investigated associations of plasma creatine concentrations with low muscle mass, low protein intake, hypoalbuminemia, low body mass index, and chronic fatigue. Arginine, guanidinoacetate, creatine and creatinine were measured in plasma, dialysate, and urinary samples of 59 hemodialysis patients. Mean age was 65 ± 15 years and 63% were male. During hemodialysis, plasma concentrations of arginine (77 ± 22 to 60 ± 19 μmol/L), guanidinoacetate (1.8 ± 0.6 to 1.0 ± 0.3 μmol/L), creatine (26 [16–41] to 21 [15–30] μmol/L) and creatinine (689 ± 207 to 257 ± 92 μmol/L) decreased (all P < 0.001). During a hemodialysis session, patients lost 1939 ± 871 μmol arginine, 37 ± 20 μmol guanidinoacetate, 719 [399–1070] μmol creatine and 15.5 ± 8.4 mmol creatinine. In sex-adjusted models, lower plasma creatine was associated with a higher odds of low muscle mass (OR per halving: 2.00 [1.05–4.14]; P = 0.04), low protein intake (OR: 2.13 [1.17–4.27]; P = 0.02), hypoalbuminemia (OR: 3.13 [1.46–8.02]; P = 0.008) and severe fatigue (OR: 3.20 [1.52–8.05]; P = 0.006). After adjustment for potential confounders, these associations remained materially unchanged. Creatine is iatrogenically removed during hemodialysis and lower plasma creatine concentrations were associated with higher odds of low muscle mass, low protein intake, hypoalbuminemia, and severe fatigue, indicating a potential role for creatine supplementation.

Profiling of Patients with COPD for Adequate Referral to Exercise-Based Care: The Dutch Model

A loss of physical functioning (i.e., a low physical capacity and/or a low physical activity) is a common feature in patients with chronic obstructive pulmonary disease (COPD). To date, the primary care physiotherapy and specialized pulmonary rehabilitation are clearly underused, and limited to patients with a moderate to very severe degree of airflow limitation (GOLD stage 2 or higher). However, improved referral rates are a necessity to lower the burden for patients with COPD and for society. Therefore, a multidisciplinary group of healthcare professionals and scientists proposes a new model for referral of patients with COPD to the right type of exercise-based care, irrespective of the degree of airflow limitation. Indeed, disease instability (recent hospitalization, yes/no), the burden of disease (no/low, mild/moderate or high), physical capacity (low or preserved) and physical activity (low or preserved) need to be used to allocate patients to one of the six distinct patient profiles. Patients with profile 1 or 2 will not be referred for physiotherapy; patients with profiles 3-5 will be referred for primary care physiotherapy; and patients with profile 6 will be referred for screening for specialized pulmonary rehabilitation. The proposed Dutch model has the intention to get the right patient with COPD allocated to the right type of exercise-based care and at the right moment.

Fibroblast growth factor 21 and protein energy wasting in hemodialysis patients

INTRODUCTION

Protein energy wasting (PEW) is the most important risk factor for morbidity and mortality in hemodialysis patients. Inadequate dietary protein intake is a frequent cause of PEW. Recent studies have identified fibroblast growth factor 21 (FGF21) as an endocrine protein sensor. This study aims to investigate the potential of FGF21 as a biomarker for protein intake and PEW and to investigate intradialytic FGF21 changes.

METHODS

Plasma FGF21 was measured using an enzyme-linked immunoassay. Complete intradialytic dialysate and interdialytic urinary collections were used to calculate 24-h urea excretion and protein intake. Muscle mass was assessed using the creatinine excretion rate and fatigue was assessed using the Short Form 36 and the Checklist Individual Strength.

RESULTS

Out of 59 hemodialysis patients (65 ± 15 years, 63% male), 39 patients had a low protein intake, defined as a protein intake less than 0.9 g/kg/24-h. Patients with a low protein intake had nearly twofold higher plasma FGF21 compared to those with an adequate protein intake (FGF21 1370 [795-4034] pg/mL versus 709 [405-1077] pg/mL;P < 0.001). Higher plasma FGF21 was associated with higher odds of low protein intake (Odds Ratio: 3.18 [1.62-7.95] per doubling of FGF21; P = 0.004), independent of potential confounders. Higher plasma FGF21 was also associated with lower muscle mass (std β: -0.34 [-0.59;-0.09];P = 0.009), lower vitality (std β: -0.30 [-0.55;-0.05];P = 0.02), and more fatigue (std β: 0.32 [0.07;0.57];P = 0.01). During hemodialysis plasma FGF21 increased by 354 [71-570] pg/mL, corresponding to a 29% increase.

CONCLUSION

Higher plasma FGF21 is associated with higher odds of low protein intake in hemodialysis patients. Secondarily, plasma FGF21 is also associated with lower muscle mass, less vitality, and more fatigue. Lastly, there is an intradialytic increase in plasma FGF21. FGF21 could be a valuable marker allowing for objective assessment of PEW.

Factors affecting the severity of fatigue in male patients with chronic obstructive pulmonary disease

BACKGROUND AND OBJECTIVES

Fatigue, the second most common symptom after dyspnea in patients with chronic obstructive pulmonary disease, impairs functional capacity and quality of life. This study aims to predict the factors that affect fatigue severity and investigate the effects of fatigue in patients with chronic obstructive pulmonary disease.

METHODS

Data were collected to assess demographic and clinical characteristics, cigarette consumption, fatigue severity (Fatigue Severity Scale), dyspnea severity (Medical Research Council Dyspnea Scale), level of physical activity (International Physical Activity Questionnaire-Short Form), and health-related quality of life (36-Item Short Form Health Survey).

RESULTS

A total of 64 male chronic obstructive pulmonary disease patients were evaluated (mean age 61.1±4.7 years, mean Fatigue Severity Scale score 39.8±14.4). The result of the linear regression model was significant and explained 84% of the variance in fatigue severity (Adjusted R-squared=0.84, F=29.48, df=60, p<.001). It showed that the Medical Research Council Dyspnea Scale score (β=.40), cigarette consumption (β=.35), and physical activity level (β=-.37) were significantly correlated with the severity of fatigue (p<.001 for all) and that they independently contributed to the prediction of severity of fatigue.

CONCLUSION

Dyspnea, cigarette consumption, and physical activity level affect fatigue severity. Additionally, physical activity level, pulmonary function, and health-related quality of life were also associated with fatigue. These findings support the assertion that it is important to measure fatigue and the factors that affect its severity.

Factors affecting the severity of fatigue in male patients with chronic obstructive pulmonary disease

BACKGROUND AND OBJECTIVES

Fatigue, the second most common symptom after dyspnea in patients with chronic obstructive pulmonary disease, impairs functional capacity and quality of life. This study aims to predict the factors that affect fatigue severity and investigate the effects of fatigue in patients with chronic obstructive pulmonary disease.

METHODS

Data were collected to assess demographic and clinical characteristics, cigarette consumption, fatigue severity (Fatigue Severity Scale), dyspnea severity (Medical Research Council Dyspnea Scale), level of physical activity (International Physical Activity Questionnaire Short-Form), and health-related quality of life (36-Item Short Form Health Survey).

RESULTS

A total of 64 male COPD patients were evaluated (mean age 61.1 ± 4.7 years, mean FSS score 39.8 ± 14.4). The result of the linear regression model was significant and explained 84% of the variance in fatigue severity (Adjusted R-squared = 0.84, F = 29.48, df = 60, p < .001). It showed that the MRC score (β = .40), cigarette consumption (β = .35), and physical activity level (β = -.37) were significantly correlated with the severity of fatigue (p < .001 for all) and that they independently contributed to the prediction of severity of fatigue.

CONCLUSION

Dyspnea, cigarette consumption, and physical activity level affect fatigue severity. Additionally, physical activity level, pulmonary function, and HRQOL were also associated with fatigue. These findings support the assertion that it is important to measure fatigue and the factors that affect its severity.

Protein Intake, Fatigue and Quality of Life in Stable Outpatient Kidney Transplant Recipients

Fatigue is a frequent complaint in kidney transplant recipients (KTR), often accompanied by poor quality of life (QoL). The role of nutrition as determinant of fatigue in KTR is largely unexplored. The aims of this study are to examine the association of protein intake with fatigue and QoL in KTR and to identify other determinants of fatigue. This cross-sectional study is part of the TransplantLines Cohort and Biobank Study (NCT03272841). Protein intake was calculated from urinary urea nitrogen (UUN) in 24-h urine samples. Fatigue was assessed by the Checklist Individual Strength (CIS) questionnaire; moderate and severe fatigue were defined as a CIS score of 20–34 and ≥ 35, respectively. QoL was assessed with the RAND-36-Item Health Survey (RAND-36). Associations of protein intake with fatigue and QoL were analyzed using multinomial logistic and linear regression analyses. We included 730 stable outpatient KTR (median age 58 year [IQR 48–65], 57% male) with a mean protein intake of 82.2 ± 21.3 g/d. Moderate and severe fatigue were present in 254 (35%) and 245 (34%) of KTR. Higher protein intake was significantly associated with lower risk of moderate fatigue (OR 0.89 per 10 g/d; 95%CI 0.83–0.98, p = 0.01), severe fatigue (OR 0.85; 95%CI 0.78–0.92, p < 0.001) and was associated with higher physical component summary score of QoL (β 0.74 per 10 g/d; 95%CI 0.39–1.09, p < 0.001). Higher BMI, a history of dialysis, glomerulonephritis as primary kidney disease and a history of combined organ transplantation were also associated with severe fatigue. In conclusion, amongst the potential modifiable factors of fatigue, higher protein intake is independently associated with lower risk of moderate and severe fatigue and with better QoL in KTR. These findings underline the need to incorporate nutritional assessment in the diagnostic work-up of fatigue. Intervention studies are needed to assess the benefits and safety of higher protein intake in KTR.

Fatigue is highly prevalent in patients with COPD and correlates poorly with the degree of airflow limitation

Background:

The objective of this study was to compare fatigue levels between subjects with and without COPD, and to investigate the relationship between fatigue, demographics, clinical features and disease severity.

Methods:

A total of 1290 patients with COPD [age 65 ± 9 years, 61% male, forced expiratory volume in 1 s (FEV1) 56 ± 19% predicted] and 199 subjects without COPD (age 63 ± 9 years, 51% male, FEV1 112 ± 21% predicted) were assessed for fatigue (Checklist Individual Strength-Fatigue), demographics, clinical features and disease severity.

Results:

Patients with COPD had a higher mean fatigue score, and a higher proportion of severe fatigue (CIS-Fatigue score 35 ± 12 versus 21 ± 11 points, p < 0.001; 49 versus 10%, p < 0.001). Fatigue was significantly, but poorly, associated with the degree of airflow limitation [FEV1 (% predicted) Spearman correlation coefficient = −0.08, p = 0.006]. Multiple regression indicated that 30% of the variance in fatigue was explained by the predictor variables.

Conclusions:

Severe fatigue is prevalent in half of the patients with COPD, and correlates poorly with the degree of airflow limitation. Future studies are needed to better understand the physical, psychological, behavioural, and systemic factors that precipitate or perpetuate fatigue in COPD.

Daytime symptoms of chronic obstructive pulmonary disease: a systematic review

There is no single source of compiled data on symptoms experienced by patients with chronic obstructive pulmonary disease (COPD) when awake and active throughout the day. The aim of this systematic review was to evaluate the prevalence, variability, and burden (i.e., bothersomeness and/or intensity), and the impact of daytime COPD symptoms on other outcomes. The review also evaluated the impact of interventions and the measures/tools used to assess daytime COPD symptoms in patients. A systematic literature search was conducted using the primary search terms "COPD", "symptoms", and "daytime" in EMBASE®, MEDLINE®, MEDLINE® In-Process, and CENTRAL in 2016, followed by an additional search in 2018 to capture any new literature that was published since the last search. Fifty-six articles were included in the review. The accumulated evidence indicated that the symptomatic burden of COPD appears greatest in the morning, particularly upon waking, and that these morning symptoms have a substantial impact on patients' ability to function normally through the day; they also worsen quality of life. A wide variety of tools were used to evaluate symptoms across the studies. The literature also confirmed the importance of pharmacotherapy in the management of daytime COPD symptoms, and in helping normalize daily functioning. More research is needed to better understand how COPD symptoms impact daily functioning and to evaluate COPD symptoms at well-defined periods throughout the day, using validated and uniform measures/tools. This will help clinicians to better define patients' needs and take appropriate action.

Nutritional Status as a Mediator of Fatigue and Its Underlying Mechanisms in Older People

Fatigue is an often-neglected symptom but frequently complained of by older people, leading to the inability to continue functioning at a normal level of activity. Fatigue is frequently associated with disease conditions and impacts health status and quality of life. Yet, fatigue cannot generally be completely explained as a consequence of a single disease or pathogenetic mechanism. Indeed, fatigue mirrors the exhaustion of the physiological reserves of an older individual. Despite its clinical relevance, fatigue is typically underestimated by healthcare professionals, mainly because reduced stamina is considered to be an unavoidable corollary of aging. The incomplete knowledge of pathophysiological mechanisms of fatigue and the lack of a gold standard tool for its assessment contribute to the poor appreciation of fatigue in clinical practice. Inadequate nutrition is invoked as one of the mechanisms underlying fatigue. Modifications in food intake and body composition changes seem to influence the perception of fatigue, probably through the mechanisms of inflammation and/or mitochondrial dysfunction. Here, we present an overview on the mechanisms that may mediate fatigue levels in old age, with a special focus on nutrition.

Organizational aspects of pulmonary rehabilitation in chronic respiratory diseases

Adult patients with chronic respiratory diseases may suffer from multiple physical (pulmonary and extra-pulmonary), emotional and social features which necessitate a comprehensive, interdisciplinary rehabilitation programme. To date, pulmonary rehabilitation programmes show a lot of variation in setting, content, frequency and duration. Future projects should strive for a standard set of assessment measures to identify patients eligible for pulmonary rehabilitation, taking disease complexity into consideration, which should result in referral to an appropriate rehabilitation setting. Local circumstances may complicate this crucial endeavour.

The holistic management of fatigue within palliative care

BACKGROUND

Fatigue is a common symptom experienced by people with cancer and other long-term, non-malignant conditions. It can be disease-related or caused by treatments such as chemotherapy or radiotherapy. Patients frequently report this as a distressing symptom and, while some international guidelines for its management exist, evidence suggests that these are not always implemented.

METHOD

This article reviews the evidence basis for fatigue management, looking at exercise, education, psychological interventions, complementary therapies and pharmacological therapy, and finds that a one-size fits all approach to fatigue management is unrealistic.

FINDINGS

Research appears to support different interventions at various points in the disease trajectory and this is of importance for service design as palliative care is increasingly introduced earlier in the patient's pathway.

CONCLUSION

Although the body of research is growing, management of fatigue caused by non-malignant conditions remains poorly evidenced, making comprehensive recommendations for these patient groups even more challenging.

Fatigue in Chronic Respiratory Diseases: Theoretical Framework and Implications For Real-Life Performance and Rehabilitation

Fatigue is a primary disabling symptom in chronic respiratory diseases (CRD) with major clinical implications. However, fatigue is not yet sufficiently explored and is still poorly understood in CRD, making this symptom underdiagnosed and undertreated in these populations. Fatigue is a dynamic phenomenon, particularly in such evolving diseases punctuated by acute events which can, alone or in combination, modulate the degree of fatigue experienced by the patients. This review supports a comprehensive inter-disciplinary approach of CRD-related fatigue and emphasizes the need to consider both its performance and perceived components. Most studies in CRD evaluated perceived fatigue as a trait characteristic using multidimensional scales, providing precious information about its prevalence and clinical impact. However, these scales are not adapted to understand the complex dynamics of fatigue in real-life settings and should be augmented with ecological assessment of fatigue. The state level of fatigue must also be considered during physical tasks as severe fatigue can emerge rapidly during exercise. CRD patients exhibit alterations in both peripheral and central nervous systems and these abnormalities can be exacerbated during exercise. Laboratory tests are necessary to provide mechanistic insights into how and why fatigue develops during exercise in CRD. A better knowledge of the neurophysiological mechanisms underlying perceived and performance fatigability and their influence on real-life performance will enable the development of new individualized countermeasures. This review aims first to shed light on the terminology of fatigue and then critically considers the contemporary models of fatigue and their relevance in the particular context of CRD. This article then briefly reports the prevalence and clinical consequences of fatigue in CRD and discusses the strengths and weaknesses of various fatigue scales. This review also provides several arguments to select the ideal test of performance fatigability in CRD and to translate the mechanistic laboratory findings into the clinical practice and real-world performance. Finally, this article discusses the dose-response relationship to training and the feasibility and validity of using the fatigue produced during exercise training sessions in CRD to optimize exercise training efficiency. Methodological concerns, examples of applications in selected diseases and avenues for future research are also provided.