People receiving dialysis in the morning have better subjective sleep quality than those who receive dialysis at other times
- Correspondence to: Dr Stephanie Thompson, Department of Medicine, University of Alberta, RTF 3064 8308 114 Street, Edmonton, Alberta, Canada T6G2V2;
Commentary on: Wang MY, Chan SF, Chang LI, et al. Better sleep quality in chronic haemodialyzed patients is associated with morning-shift dialysis: a cross-sectional observational study. Int J Nurs Stud 2013;50:1468–73.
Implications for practice and research
Assessment of sleep quality, with attention to disease and treatment-related factors, should be incorporated into the routine care of haemodialysis patients.
Rigorous studies aimed at evaluating interventions for improved sleep in this population are needed.
Sleep disturbances are a common problem among haemodialysis patients, with an estimated prevalence of 50% to 80%.1 The implications of disturbed sleep are substantial; compared with haemodialysis patients who do not report sleep disturbances, poor sleep is independently associated with lower health-related quality of life and an increased relative risk in mortality of 16%.2 As the timing of the dialysis shift may influence sleep–wake patterns, Wang and colleagues investigated the relation between the timing of the dialysis shift and the sleep quality.
Wang and colleagues used a cross-sectional study design to evaluate the relation between dialysis shift times and sleep quality in patients undergoing chronic haemodialysis. The study setting was a single, university-affiliated dialysis centre in Taiwan. The Pittsburgh Sleep Quality Index (PSQI) was completed by self-report and used to measure the sleep quality. Covariates included depression, measured by the Beck Depression Inventory (BDI)-II; anxiety, measured by the Beck Anxiety Inventory (BAI); stimulant beverage consumption; and clinical and demographic factors. The outcome comparison was between the morning dialysis shift and ‘other’ (afternoon or evening) dialysis shifts. Patients were excluded if they were hospitalised, immobilised or dialysed less than twice weekly for under 3 h.
A sample of 220 patients was obtained; approximately 94% of study questionnaires were completed. The mean age of participants was 52.4 years old and the mean duration of dialysis for participants was approximately 7 years. After adjustment for factors previously shown to be associated with sleep quality in haemodialysis patients and baseline differences, morning shift dialysis was significantly associated with better sleep quality compared with the other shift time (β=0.15, p=0.01). Consistent with previous studies, depression was associated with poor sleep quality (β=0.42, p=0.001) as were anxiety and tea drinking (but not coffee drinking). In contrast to previous studies, age and diabetes were not associated with subjective sleep quality.1
The prevalence of self-reported poor sleep quality is considerably higher among haemodialysis patients compared with the general population.2 Disturbances in sleep quality are described as difficulty in initiating or maintaining sleep, restlessness, jerking limbs and/or daytime somnolence.3 As with the general population, numerous factors contribute to poor sleep quality in haemodialysis patients. Notably though, how end-stage renal disease and its treatment contribute to poor sleep is not completely understood.
Previous studies evaluating dialysis shift time and sleep quality have produced conflicting results. It is hypothesised that haemodialysis-related changes in body temperature could disrupt the circadian core body temperature cycle.4 However, limited data show how alterations in body temperature during dialysis can influence the subsequent sleep patterns. Importantly, the timing of dialysis shifts is also associated with other factors that may influence sleep, such as variations in light exposure and daily physical and social activity patterns.
This study is important because it draws attention to an important but often unaddressed clinical issue, while it also has implications for the future research: first, although Wang and colleagues provide information on caffeine consumption and diabetic status, to make meaningful inferences more detailed information on patient characteristics, such as medications and comorbidities,5 and behaviours, such as napping during and after dialysis, are required. Second, and as noted by the authors, the patient preference may also influence the time of dialysis shift; therefore, sleep habits may confound the association with poor sleep and shift time. Given the clinical significance of poor sleep, data from longitudinal studies are required to inform what factors are important to target in randomised trials. In the interim, assessment of sleep quality, with attention to disease-related and treatment-related factors—particularly depression, should be incorporated into the routine care of haemodialysis patients.