Sleep Disturbance in Patients With End-Stage Renal Disease

Patients will not selected based on presence/absence of sleep disturbance. Patients will be prioritized for recruitment if they were active on the transplant waitlist or a change in RRT modality is planned.

Patients will be selected for inclusion if they were >16 years old, competent to independently undertake the informed consent process and are currently on RRT or planned to start RRT in the next three months. The following exclusion criteria will be applied: dementia, active malignancy, major psychiatric disorder, home oxygen therapy, CPAP therapy, and regular benzodiazepine use.

Baseline Evaluation

Baseline evaluation includes the following:

• Demographics and clinical parameters including medications and caffeine intake
• Dialysis prescription and adequacy (weekly standardised Kt/V)
• Laboratory data (haemoglobin, iron, phosphate, PTH)
• Subjective sleep quality as measured by Berlin Questionnaire, Epworth Sleepiness Scale, Pittsburgh Sleep Quality Index and International Restless Leg Syndrome Questionnaire
• Quality of Life as assessed by the 36 Item Short Form Survey (SF-36), Beck Depression Index and Centre for Epidemiologic Studies-Depression Scale
• Cognitive assessment as measured by Trail Making Tests 1 \& 2, Category Fluency, Controlled Oral Word Association Test and Hopkins Verbal Learning Test
• Unattended home polysomnography set-up up by investigator who was blinded to the results of the above assessments
• Wrist actigraphy for 3-5 continuous days (Philips Respironics Actiwatch 2 System)

Follow-up Evaluation following RRT Modality Change Follow-up evaluation will be performed in the same way as baseline evaluation at three - six months post switch of RRT modality. As the impact of NHHD is of particular interest, follow-up evaluation will be performed at one and six months post switch to NHHD in those patients who switched to NHHD. The follow-up home PSG was performed on an 'on-dialysis' night and an 'off-dialysis' night to evaluate the impact of the nocturnal procedure itself on sleep.

Data Analysis A sleep technician, blinded to the questionnaire results, compiles the PSG analysis and reports in accordance with the American Academy of Sleep Medicine (AASM) manual for the Scoring of Sleep and Associated Events (40). Actigraphy analysis is reported using Philips Respironics Actiwatch Software.

Statistical methods Statistical analysis will be performed using Stata V14 and Prism V6. All p values \<0.05 will be considered statistically significant. Mean data and standard deviation data will be analysed using independent samples t-test and repeated measures analysis of variance (ANOVA). Nominal data will be analysed using chi-squared analysis.

Safety \& Tolerability Reports were reviewed with a Respiratory Consultant with specialist interest in Sleep Medicine on a regular basis and abnormal results were discussed in detail. If specific therapy is indicated on the basis of the research tests, the treating nephrologist will be informed and a management plan recommended.