title: Validation of a novel sleep-quality questionnaire to assess sleep in the coronary care unit: a polysomnography study.
abstract: BACKGROUND
  The sleep of patients admitted to coronary care unit (CCU) may be compromised. A feasible and cost-effective tool to evaluate sleep in this scenario could provide important data. The aim of this study was to evaluate sleep with a questionnaire developed specifically for the CCU and to validate it with polysomnography (PSG).
  
  
  METHODS
  Ninety-nine patients (68% male; 56 ± 10 years old) with acute coronary syndrome were included. PSG was performed within 36 h of admission. A specific 18-question questionnaire (CCU questionnaire) was developed and applied after the PSG. Cronbach's alpha test was used to validate the questionnaire. The Spearman test was used to analyze the correlation between the PSG variables and the questionnaire, and the Kruskal-Wallis test was used to compare the PSG variables among patients with good, regular, or poor sleep.
  
  
  RESULTS
  The total sleep time was 265 ± 81 min, sleep efficiency 62 ± 18%, REM sleep 10 ± 7%, apnea/hypopnea index 15 ± 23, and the arousal index 24 ± 15. Cronbach's alpha test was 0.69. The CCU questionnaire showed correlation with the sleep efficiency evaluated by PSG (r: 0.52; p < 0.001). Sleep quality was divided into three categories according to the CCU questionnaire: patients with good sleep had a sleep efficiency of 72 ± 9%, better than those with a regular or poor sleep (60 ± 16% and 53 ± 20%, respectively; p < 0.01).
  
  
  CONCLUSIONS
  The CCU questionnaire is a feasible and reliable tool to evaluate sleep in the CCU, showing correlation with the PSG sleep efficiency.
authors.affiliation: Discipline of Cardiology, Department of Internal Medicine, Federal University of São Paulo/Escola Paulista de Medicina, Sao Paulo, Brazil. Electronic address: ljstorti@hotmail.com.
authors.forename: Luciana J
authors.initials: LJ
authors.lastname: Storti
authors.affiliation: Discipline of Cardiology, Department of Internal Medicine, Federal University of São Paulo/Escola Paulista de Medicina, Sao Paulo, Brazil.
authors.forename: Denise M
authors.initials: DM
authors.lastname: Servantes
authors.affiliation: Discipline of Cardiology, Department of Internal Medicine, Federal University of São Paulo/Escola Paulista de Medicina, Sao Paulo, Brazil.
authors.forename: Melania
authors.initials: M
authors.lastname: Borges
authors.affiliation: Discipline of Sleep Biology and Medicine, Department of Psychobiology, Federal University of São Paulo/Escola Paulista de Medicina, Sao Paulo, Brazil.
authors.forename: Lia
authors.initials: L
authors.lastname: Bittencourt
authors.affiliation: Discipline of Cardiology, Department of Internal Medicine, Federal University of São Paulo/Escola Paulista de Medicina, Sao Paulo, Brazil.
authors.forename: Fabrizio U
authors.initials: FU
authors.lastname: Maroja
authors.affiliation: Discipline of Sleep Biology and Medicine, Department of Psychobiology, Federal University of São Paulo/Escola Paulista de Medicina, Sao Paulo, Brazil.
authors.forename: Dalva
authors.initials: D
authors.lastname: Poyares
authors.affiliation: Discipline of Sleep Biology and Medicine, Department of Psychobiology, Federal University of São Paulo/Escola Paulista de Medicina, Sao Paulo, Brazil.
authors.forename: Patrick R
authors.initials: PR
authors.lastname: Burke
authors.affiliation: Discipline of Cardiology, Department of Internal Medicine, Federal University of São Paulo/Escola Paulista de Medicina, Sao Paulo, Brazil.
authors.forename: Vinicius B
authors.initials: VB
authors.lastname: Santos
authors.affiliation: Discipline of Cardiology, Department of Internal Medicine, Federal University of São Paulo/Escola Paulista de Medicina, Sao Paulo, Brazil.
authors.forename: Rita S L
authors.initials: RS
authors.lastname: Moreira
authors.affiliation: Discipline of Cardiology, Department of Internal Medicine, Federal University of São Paulo/Escola Paulista de Medicina, Sao Paulo, Brazil.
authors.forename: Frederico J N
authors.initials: FJ
authors.lastname: Mancuso
authors.affiliation: Discipline of Cardiology, Department of Internal Medicine, Federal University of São Paulo/Escola Paulista de Medicina, Sao Paulo, Brazil.
authors.forename: Angelo A V
authors.initials: AA
authors.lastname: de Paola
authors.affiliation: Discipline of Sleep Biology and Medicine, Department of Psychobiology, Federal University of São Paulo/Escola Paulista de Medicina, Sao Paulo, Brazil.
authors.forename: Sergio
authors.initials: S
authors.lastname: Tufik
authors.affiliation: Discipline of Cardiology, Department of Internal Medicine, Federal University of São Paulo/Escola Paulista de Medicina, Sao Paulo, Brazil.
authors.forename: Antonio C C
authors.initials: AC
authors.lastname: Carvalho
authors.affiliation: Discipline of Cardiology, Department of Internal Medicine, Federal University of São Paulo/Escola Paulista de Medicina, Sao Paulo, Brazil.
authors.forename: Fatima D
authors.initials: FD
authors.lastname: Cintra
mesh_terms: D054058:Acute Coronary Syndrome / Q000150:complications / Q000628:therapy; D003325:Coronary Care Units; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D017286:Polysomnography; D015203:Reproducibility of Results; D012890:Sleep; D012893:Sleep Wake Disorders / Q000175:diagnosis* / Q000209:etiology; D012895:Sleep, REM; D011795:Surveys and Questionnaires / Q000592:standards
keywords: Acute coronary syndrome; Coronary care unit; Polysomnography; Questionnaire design; Sleep quality