The Feasibility of Semi-Continuous and Multi-Frequency Thoracic Bioimpedance Measurements by a Wearable Device during Fluid Changes in Hemodialysis Patients.

Repeated single-point measurements of thoracic bioimpedance at a single (low) frequency are strongly related to fluid changes during hemodialysis. Extension to semi-continuous measurements may provide longitudinal details in the time pattern of the bioimpedance signal, and multi-frequency measurements may add in-depth information on the distribution between intra- and extracellular fluid. This study aimed to investigate the feasibility of semi-continuous multi-frequency thoracic bioimpedance measurements by a wearable device in hemodialysis patients. Therefore, thoracic bioimpedance was recorded semi-continuously (i.e., every ten minutes) at nine frequencies (8-160 kHz) in 68 patients during two consecutive hemodialysis sessions, complemented by a single-point measurement at home in-between both sessions. On average, the resistance signals increased during both hemodialysis sessions and decreased during the interdialytic interval. The increase during dialysis was larger at 8 kHz (∆ 32.6 Ω during session 1 and ∆ 10 Ω during session 2), compared to 160 kHz (∆ 29.5 Ω during session 1 and ∆ 5.1 Ω during session 2). Whereas the resistance at 8 kHz showed a linear time pattern, the evolution of the resistance at 160 kHz was significantly different (p < 0.0001). Measuring bioimpedance semi-continuously and with a multi-frequency current is a major step forward in the understanding of fluid dynamics in hemodialysis patients. This study paves the road towards remote fluid monitoring.

Fatigue in Patients Receiving Maintenance Hemodialysis: A Review.

Fatigue surrounding hemodialysis treatments is a common and often debilitating symptom that impacts patients' quality of life. Intradialytic fatigue develops or worsens immediately before hemodialysis and persists through the dialysis treatment. Little is known about associated risk factors or pathophysiology, although it may relate to a classic conditioning response. Postdialysis fatigue (PDF) develops or worsens after hemodialysis and may persist for hours. There is no consensus on how to measure PDF. Estimates for the prevalence of PDF range from 20%-86%, likely due to variation in methods of ascertainment and participant characteristics. Several hypotheses seek to explain the pathophysiology of PDF, including inflammation, hypothalamic-pituitary-adrenal axis dysregulation, and osmotic and fluid shifts, but none is currently supported by compelling or consistent data. PDF is associated with several clinical factors, including cardiovascular and hemodynamic effects of the dialysis procedure, laboratory abnormalities, depression, and physical inactivity. Clinical trials have reported hypothesis-generating data about the utility of cold dialysate, frequent dialysis, clearance of large middle molecules, treatment of depression, and exercise as potential treatments. Existing studies are often limited by sample size, lack of a control group, observational design, or short intervention duration. Robust studies are needed to establish the pathophysiology and management of this important symptom.

mHealth-based experience sampling method to identify fatigue in the context of daily life in haemodialysis patients.

Background: Fatigue in haemodialysis (HD) patients is a prevalent but complex symptom impacted by biological, behavioural, psychological and social variables. Conventional retrospective fatigue questionnaires cannot provide detailed insights into symptom variability in daily life and related factors. The experience sampling methodology (ESM) overcomes these limitations through repeated momentary assessments in patients' natural environments using digital questionnaires. This study aimed to gain in-depth understanding of HD patients' diurnal fatigue patterns and related variables using a mobile Health (mHealth) ESM application and sought to better understand the nature of their interrelationships. Methods: Forty HD patients used the mHealth ESM application for 7 days to assess momentary fatigue and potentially related variables, including daily activities, self-reported physical activity, social company, location and mood. Results: Multilevel regression analyses of momentary observations (n = 1777) revealed that fatigue varied between and within individuals. Fatigue was significantly related to HD treatment days, type of daily activity, mood and sleep quality. Time-lagged analyses showed that HD predicted higher fatigue scores at a later time point (ß = 0.22, P = 0.013). Interestingly, higher momentary fatigue also significantly predicted more depressed feelings at a later time point (ß = 0.05, P = 0.019) but not the other way around. Conclusions: ESM offers novel insights into fatigue in chronic HD patients by capturing informative symptom variability in the flow of daily life. Electronic ESM as a clinical application may help us better understand fatigue in HD patients by providing personalized information about its course and relationship with other variables in daily life, paving the way towards personalized interventions.

Daily physical activity in patients on chronic haemodialysis and its relation with fatigue and depressive symptoms.

OBJECTIVE: Fatigue and depressed mood are considered main impediments to physical activity in haemodialysis (HD) patients. A better understanding of their interrelationships is crucial to develop effective therapies. Moreover, measurement of daily physical activity (DPA) in HD patients is tricky, as it is usually assessed by subjective self-report questionnaires. Therefore, we aimed to objectively measure sponteanous DPA with motion sensors and to explore its relation with fatigue and depressive symptoms. METHODS: DPA was assessed for seven consecutive days in 37 HD patients based on their daily step count measured with the SenseWear™ Armband. The Fatigue Severity Scale (FSS) and Beck Depression Inventory-II (BDI-II) were administered to evaluate fatigue and depressed mood. RESULTS: Median DPA was 2424 steps/day, (IQR:892-4545). In 81% of subjects, DPA felt within a sedentary lifestyle classification, as they made < 5.000 steps/day. DPA did not correlate with fatigue (rs = 0.04, p = 0.832), and did not significantly differ between patients categorized as clinically fatigued (n = 23, FSS ≥ 4) or not (n = 14, FSS < 4) (p = 0.654, d = 0.20). Although low-depressed subjects (n = 19, BDI-II ≤ 13) made on average 1.7 times more steps/day than high-depressed subjects (n = 18, BDI-II > 13) (p = 0.111, d = 0.60), depressive mood did also not correlate significantly with DPA (rs = - 0.23, p = 0.175). CONCLUSION: Objective assessment of DPA with motion sensors is feasible in HD patients and allows identifying a sedentary lifestyle. Our results suggest that spontanous DPA is determined by age rather than by fatigue or mood.

Unraveling Fatigue in Hemodialysis Patients: Comparing Retrospective Reports to Real-Time Assessments With an mHealth Experienced Sampling Method.

CONTEXT: Fatigue is prevalent among hemodialysis (HD) patients and associated with depressive mood. To advance our understanding of its etiology and develop appropriate treatments, reliable measurement instruments are needed. However, conventional fatigue and mood questionnaires are prone to bias because of their retrospective nature and may misrepresent or overestimate actual symptom experience (i.e., the so-called memory-experience gap). Experience sampling methodology (ESM) overcomes this limitation through repeated real-time assessments in patients' natural environment, thereby providing reliable and ecologically valid data. OBJECTIVES: We investigated to what extent retrospective symptom reporting accurately represents real-time experiences of fatigue and mood in HD patients using an ESM mobile Health application (PsyMate™; smartHealth GmbH, Luxembourg). METHODS: Forty HD patients used the PsyMate for one week to assess real-time fatigue and mood. In addition, they retrospectively evaluated their symptom experience completing end-of-day and end-of-week questionnaires as well as the conventional Fatigue Severity Scale and Hospital Anxiety and Depression Scale. RESULTS: Results of real-time observations (N = 1777) showed that fatigue and mood varied between and within individuals. Retrospective end-of-week fatigue evaluation was significantly higher than the average real-time fatigue score; t(38) = 3.54, P = 0.001, and d = 0.57. Fatigue Severity Scale and Hospital Anxiety and Depression Scale correlated moderately to strong with the average ESM score for fatigue and mood: r = 0.66 and r = 0.77, respectively. CONCLUSION: Retrospective fatigue assessment may lead to overestimation of real-time symptom experience. ESM provides detailed insight and personalized information about symptom experiences, which may be crucial for the design of more targeted and personalized interventions for fatigue and mood problems in HD patients.

Serum interleukin-6 and endotoxin levels and their relationship with fatigue and depressive symptoms in patients on chronic haemodialysis.

BACKGROUND: Little is known about the underlying aetiology of fatigue in haemodialysis (HD) patients apart from a significant association and overlapping symptomatology with depressive symptoms. Growing evidence exists for the involvement of the immune system, by pro-inflammatory cytokines, in the development of fatigue in other inflammatory diseases. In HD patients, increased exposure to bacterial endotoxins may contribute to an inflammatory response and may potentially lead to fatigue. We therefore aimed (i) to assess the interrelationship between serum endotoxin (EA) levels, interleukin-6 (IL-6) levels and fatigue in HD patients; (ii) to evaluate whether there is a relationship between depressive symptoms and inflammation as well and (iii) to what extent depressive symptoms and fatigue are related to each other. METHODS: Fatigue and depressive symptoms in daily life were assessed in 59 individuals using the SF-36 vitality subscale and the Geriatric Depression Scale. Blood samples were collected on a mid-week dialysis session to determine EA levels, through the Endotoxin Activity Assay (EAA™), and IL-6 concentrations, through the commercially available Abcam ELISA (Enzyme-Linked Immunosorbent Assay) kit. RESULTS: EA, IL-6 levels and depressive symptoms were significantly correlated with fatigue. EA levels and depressive symptoms were significant predictors of fatigue, explaining 31% of its variance. However, EA and IL-6 were not significantly associated with depression. CONCLUSIONS: Fatigue in HD patients may be related to endotoxemia and inflammation through IL-6. Furthermore, fatigue is significantly associated with depressive symptoms. Future research into the causal interrelationship of inflammation, fatigue and depression in HD patients might lead to potential targets for therapeutic strategies.

Exploring the Diurnal Course of Fatigue in Patients on Hemodialysis Treatment and Its Relation With Depressive Symptoms and Classical Conditioning.

CONTEXT: Fatigue is one of the most prevalent symptoms among hemodialysis (HD) patients. To design effective treatments, it is crucial to understand the diurnal pattern of fatigue in this population. OBJECTIVES: The objectives of this study were to assess diurnal changes in fatigue in patients undergoing hemodialysis and their relation with depressive symptoms and to explore whether fatigue may become a classically conditioned response to the hospital environment. METHODS: A prospective, observational study was conducted in 51 HD patients. Subjects repeatedly rated their current fatigue on three different days during one week of hemodialysis treatment to capture changes in momentary fatigue. First, on an HD treatment day, fatigue was measured one hour before and immediately before dialysis, as well as immediately after dialysis and again at 22:00 pm Second, on the postdialysis day and on the seventh weekday (when patients had not received treatment on the previous day), fatigue was measured at the same moments in time as the two measurements before dialysis on the treatment day. Beck Depression Inventory-II and Fatigue Severity Scale were administered to evaluate depressive mood and fatigue severity in daily life. RESULTS: Fatigue increased as a result of hemodialysis treatment over the entire sample. However, diurnal fatigue patterns differed significantly between individuals high and low in depressive symptoms, with the former being fatigued more constantly throughout the day, and the latter experiencing increases in fatigue due to treatment. Pretreatment fatigue experienced in the hospital environment followed a pattern consistent with the development of a classically conditioned response. CONCLUSION: Diurnal fatigue patterns during hemodialysis treatment are associated with depressive symptoms, and classical conditioning may play a role in the experience of pretreatment fatigue.