The number of chronic kidney disease (CKD) patients is rapidly growing, with a 6% to 8% increase in dialysis patients per annum, and it has been described as a worldwide epidemic (Levin, 2003). Management of CKD is complex and demanding, particularly maintenance dialysis for patients whose renal functioning is insufficient to sustain life (end-stage kidney disease, ESKD). Overall, the physical and mental well-being of CKD patients tends to be greatly compromised and with deteriorating kidney function, patients experience numerous debilitating symptoms (Murtagh, Addington-Hall, & Higginson, 2007; Murtagh, Addington-Hall, Edmonds, et al., 2007). One of the most common and disruptive symptoms in this setting is fatigue, particularly among dialysis patients, affecting at least 1 in 2 patients. Fatigue is a complex and subjective in nature symptom, likely to involve sociodemographic, clinical, and psychological factors in its aetiology. To date, studies have mainly focused on the sociodemographic and clinical correlates of fatigue in this setting and the role of psychological factors remains poorly understood. Pharmacotherapy and exercise are currently relied on for the management of fatigue in this setting, with limited effectiveness and not suitable for all patients. To date, fatigue-specific evidence-based psychological treatments in this patient population are absent. This is in stark contrast to the growing evidence available in support of psychosocial interventions, such as cognitive-behavioural therapy (CBT), in other long-term physical conditions, like cancer, multiple sclerosis, and rheumatoid arthritis. This thesis presents a series of studies that contributed to the development of a theoretical biopsychosocial model of fatigue in ESKD and a related intervention to support management of fatigue in this patient population. A prospective study of fatigue with yearly assessments over three years among prevalent in-centre haemodialysis patients (N=174 at baseline; N=118 at 12 months, N=84 at 24 months, and N=66 at 36 months) further demonstrated the negative implications of fatigue on clinical outcomes, where fatigue was predictive of an increased risk of death and decreased likelihood of transplantation among patients. Distress and reduced functioning appeared to play an important role in the association between fatigue severity and clinical outcomes. As fatigue is ubiquitous and patients are likely to experience recurrent symptoms of fatigue, especially following dialysis sessions; its impact on clinical outcomes can be weakened by reducing its impact on functioning in mood. A meta-analytic systematic review of psychosocial interventions for the management of fatigue in ESKD found promising evidence in favour of such interventions. There was evidence for greater effectiveness of interventions including stress-management/relaxation techniques, evaluated among fatigued samples meeting diagnostic thresholds, against passive/non-active comparison groups. However, the studies were generally of poor methodological quality and with high heterogeneity. Nevertheless, this review highlighted the potential value of psychosocial interventions for the management of fatigue in this patient population. In order to gather a comprehensive understanding of the factors involved in fatigue of ESKD patients, a mixed-methods approach was used. A qualitative study of ESKD patients, across renal replacement therapy (RRT) modalities (N=25) provided insights into fatigue-related beliefs, consequences of fatigue on functioning and mood, and strategies utilised for the management of fatigue. Importantly, this study also revealed the value of social support in this setting and offered insights on differences in fatigue experiences by treatment modality. Data from the prospective 3-year study of fatigue among prevalent in-centre haemodialysis patients mentioned above was also utilised to assess the trajectories of fatigue severity and fatigue-related functional impairment over time and to identify factors associated with change over time. Based on the cross-sectional findings, mood, cognitive and behavioural variables explained substantial variance in fatigue and its impact of functioning, above and beyond the role of sociodemographic and clinical factors (Chilcot, Moss-Morris, et al., 2016). Yet, over time, only ethnicity appeared to play a particularly important role in fatigue severity, while damage beliefs predicted an increase in fatigue-related functional impairment each year. However, the data strongly suggested that fatigue outcomes vary by dialysis vintage, where in the first 24 months from dialysis initiation, there was a significant reduction in fatigue severity, but after that time, a small increase in fatigue severity could be observed. Data generated from the reviews and empirical studies was used as a basis for the development of a biopsychosocial model of renal fatigue by merging the findings and mapping them onto the theoretical constructs of Leventhal’s Common-Sense Model (CSM) and the cognitive-behavioural (CB) model (Wessely, Sharpe, & Hotopf, 1998). This theoretical model was subsequently translated into a cognitive-behavioural (CBT) treatment formulation following the Intervention Mapping framework (Bartholomew, Parcel, & Kok, 1998) and Yardley, Ainsworth, Arden-Close, and Muller (2015)’s person-based approach. The content, structure and design of the treatment protocol were shaped by input from patient and public representatives, as well as, a multi-disciplinary team, consisting of nephrologists, renal psychologists, counsellors, and health psychologists. The Cognitive-Behavioural Therapy for Renal Fatigue (BReF) treatment protocol is a 4 to 6-week guided self-management intervention aimed specifically at fatigue in ESKD. Its feasibility, acceptability, and potential efficacy were evaluated in a feasibility randomised-controlled trial among prevalent in-centre haemodialysis patients (N=18). According to the preliminary findings, based on the sample available to date, improvements in fatigue severity, depression, and anxiety following the intervention were observed based on the qualitative and quantitative data. There was also indication of its acceptability to patients according the qualitative data. However, uptake of the intervention was low which suggests that it is not feasible in its current form. The work described in this thesis has improved our understanding of fatigue in ESKD, addressing research gaps in the literature to date, particularly around change in fatigue over time, the role of psychological factors in fatigue, and the potential for a psychological intervention for the management of fatigue. The BReF intervention appears to have potential as a treatment pathway for fatigue among haemodialysis patients in the UK; however, it requires further adaption and evaluation before implementation is possible in clinical practice.
| Date of Award | 1 Apr 2019 |
|---|
| Original language | English |
|---|
| Awarding Institution | |
|---|
| Supervisor | Joseph Chilcot (Supervisor), Rona Moss-Morris (Supervisor) & Iain Macdougall (Supervisor) |
|---|