Cardiovascular risk and mortality in end-stage renal disease patients undergoing dialysis: sleep study, pulmonary function, respiratory mechanics, upper airway collapsibility, autonomic nervous activity, depression, anxiety, stress and quality of life: a prospective, double blind, randomized controlled clinical trial
Authors: dos Reis Santos Israel , Danaga Aline Roberta , de Carvalho Aguiar Isabella , Oliveira Ezequiel Fernandes , Dias Ismael Souza , Urbano Jessica Julioti , Martins Aline Almeida , Ferraz Leonardo Macario , Fonsêca Nina Teixeira , Fernandes Virgilio , Fernandes Vinicius Alves Thomaz , Lopes Viviane Cristina Delgado , Leitão Filho Fernando Sérgio Studart , Nacif Sérgio Roberto , de Carvalho Paulo de Tarso Camillo , Sampaio Luciana Maria Malosá , Giannasi Lílian Christiane , Romano Salvatore , Insalaco Giuseppe , Araujo Ana Karina Fachini , Dellê Humberto , Souza Nadia Karina Guimarães , Giannella-Neto Daniel , Oliveira Luis Vicente Franco 
Published: October 2013

Abstract

Background
Chronic kidney disease (CKD) is one of the most serious public health problems. The increasing prevalence of CKD in developed and developing countries has led to a global epidemic. The hypothesis proposed is that patients undergoing dialysis would experience a marked negative influence on physiological variables of sleep and autonomic nervous system activity, compromising quality of life.

Methods/Design
A prospective, consecutive, double blind, randomized controlled clinical trial is proposed to address the effect of dialysis on sleep, pulmonary function, respiratory mechanics, upper airway collapsibility, autonomic nervous activity, depression, anxiety, stress and quality of life in patients with CKD. The measurement protocol will include body weight (kg); height (cm); body mass index calculated as weight/height2; circumferences (cm) of the neck, waist, and hip; heart and respiratory rates; blood pressures; Mallampati index; tonsil index; heart rate variability; maximum ventilatory pressures; negative expiratory pressure test, and polysomnography (sleep study), as well as the administration of specific questionnaires addressing sleep apnea, excessive daytime sleepiness, depression, anxiety, stress, and quality of life.

Discussion
CKD is a major public health problem worldwide, and its incidence has increased in part by the increased life expectancy and increasing number of cases of diabetes mellitus and hypertension. Sleep disorders are common in patients with renal insufficiency. Our hypothesis is that the weather weight gain due to volume overload observed during interdialytic period will influence the degree of collapsibility of the upper airway due to narrowing and predispose to upper airway occlusion during sleep, and to investigate the negative influences of haemodialysis in the physiological variables of sleep, and autonomic nervous system, and respiratory mechanics and thereby compromise the quality of life of patients.

Trial registration
The protocol for this study is registered with the Brazilian Registry of Clinical Trials (ReBEC RBR-7yhr4w and World Health Organization under Universal Trial Number UTN: U1111-1127-9390 [http://www.ensaiosclinicos.gov.br/rg/RBR-7yhr4w/]).