Nocturnal dialysis improves sleep apnea more than daytime dialysis: a meta-analysis of crossover studies

Associations between nutritional factors and excessive daytime sleepiness in older patients with chronic kidney disease

BACKGROUND

Excessive daytime sleepiness (EDS) is prevalent in not only older adults, but also patients with chronic kidney disease (CKD), and is associated with higher risks of morbidity and mortality.

AIMS

The aim of the present study is to determine associations between EDS and nutritional status and serum nutrient levels in older patients with CKD.

METHODS

This cross-sectional study included 367 patients (aged ≥ 65 years) with CKD (eGFR < 60 ml/min/1.73 m² and/or > 30 mg/day of albuminuria for > 3 months). EDS was recorded using the Epworth Sleepiness Scale (a score of ≥ 11). Malnutrition was diagnosed according to the Mini Nutritional Assessment (MNA) tool (a score of < 17).

RESULTS

The mean age was 81 ± 7 years, and 248 (67%) were female. EDS was seen in 99 (26.9%) patients. Those with EDS had significantly lower MNA scores and more frequent malnutrition than those without EDS (p < 0.05). In multivariable analysis adjusted for age, sex, cerebrovascular disease, dementia, number of drugs, and number of urinations at night, and the Charlson Comorbidity Index the relationship between malnutrition and EDS persisted (OR 2.58, 95% CI 1.38-4.83, p = 0.003). There was no significant difference between the presence of EDS and serum levels or deficiencies of vitamin D, vitamin B₁₂, and folate (p > 0.05).

CONCLUSIONS

EDS is associated with malnutrition in older patients with CKD. Therefore, EDS and nutritional status should be evaluated together in clinical practice. However, future studies are needed to determine the direction of the association between malnutrition and EDS and to evaluate if dietary intervention can improve EDS.

The complexity of sleep disorders in dialysis patients

Background

Dialysis patients experience a high burden of physical and emotional symptoms directly affecting their sleep and quality of life. In this study, objective and subjective measurements to quantify sleep were performed, compared with those of healthy controls, and associated with burden of comorbidity and uraemic toxicity.

Methods

A total of 64 dialysis patients were included—10 peritoneal dialysis, 42 in-centre daytime haemodialysis (HD) and 12 in-centre nocturnal HD patients—as well as one-to-one age- and gender-matched healthy controls. Assumed and actual sleep time, sleep efficiency and fragmentation index were measured by actigraphy for at least two consecutive nights. Patients and controls also completed Insomnia Severity Index (ISI) and Pittsburgh Sleep Quality Index (PSQI) questionnaires. The patients’ blood was sampled to determine concentrations of a representative series of uraemic toxins and the Davies–Stoke comorbidity index was derived from medical records.

Results

Apart from the assumed sleep time, all objectively and subjectively measured sleep parameters were worse in the dialysis group compared with the healthy controls. No differences were seen in any of the measured sleep parameters among the different dialysis groups. None of the objectively measured sleep parameters were associated with ISI or PSQI scores in dialysis patients, while sleep times were related to the subjective scores in the healthy cohort. Objectively assessed sleep parameters were associated to neither the uraemic toxicity load nor the Davies–Stoke score.

Conclusions

Independent of the modality, dialysis patients have sleep quality much worse than age- and gender-matched healthy controls. The objectively measured sleep parameters could not be associated to the subjective score, uraemic toxicity or comorbidity score, highlighting the need for objective measurements of sleep and clinical guidelines to aid patient management.

Is kidney a new organ target in patients with obstructive sleep apnea? Research priorities in a rapidly evolving field

The bidirectional relationship between sleep disordered breathing and chronic kidney disease (CKD) has recently gained a lot of interest. Several lines of evidence suggest the high prevalence of coexistent obstructive sleep apnea (OSA) in patients with CKD and end-stage renal disease (ESRD). In addition, OSA seems to result in loss of kidney function in some patients, especially in those with cardio-metabolic comorbidities. Treatment of CKD/ESRD and OSA can alter the natural history of each other; still better phenotyping with selection of appropriate treatment approaches is urgently needed. The aim of this narrative review is to provide an update of recent studies on epidemiological associations, pathophysiological interactions, and management of patients with OSA and CKD or ESRD.