title: [Night-to-night variability of the obstructive sleep apnoea-hypopnoea syndrome].
abstract: The apnoea-hypopnoea index (AHI) is the primary measurement used to characterize the obstructive sleep apnoea-hypopnoea syndrome (OSAHS). Despite its popularity, there are limiting factors to its application such as night-to-night variability.
  
  
  OBJECTIVE
  To evaluate the variability of AHI in the OSAHS.
  
  
  METHODS
  A prospective study was designed in our university hospital's sleep unit. Adults with clinical suspicion of OSAHS underwent 2 consecutive nights of polysomnographic recording. The population was divided in two groups according to an AHI>or<10. Patients with psychiatric disorders or professions that might result in sleep deprivation or an altered sleep/wake cycle were excluded.
  
  
  RESULTS
  Twenty patients were enrolled. The mean age was 50.6±9.3 years. OSAHS was mild in 4 cases, moderate in 6 cases and severe in 8 cases. AHI was less than 5 in two cases. AHI values were not significantly altered throughout both recording nights (33.2 vs. 31.8 events/h). A significant positive correlation was found between AHI measured on the first and the second night. However, a significant individual variability was noted. Comparison between both patient's groups showed a correlation between AHI and the body mass index.
  
  
  CONCLUSIONS
  This study demonstrates that the AHI in OSAHS patients is well correlated between two consecutive nights. However, a significant individual variability should be taken into consideration, especially when AHI is used in the classification of OSAHS or as a criterion of therapeutic success.
authors.affiliation: Unité de recherche 12SP06, service de pneumologie, hôpital La Rabta, faculté de médecine de Tunis, université de Tunis El Manar, 1007 Tunis, Tunisie. Electronic address: mjid_meriem@hotmail.fr.
authors.forename: M
authors.initials: M
authors.lastname: Mjid
authors.affiliation: Unité de recherche 12SP06, service de pneumologie, hôpital La Rabta, faculté de médecine de Tunis, université de Tunis El Manar, 1007 Tunis, Tunisie.
authors.forename: Y
authors.initials: Y
authors.lastname: Ouahchi
authors.affiliation: Unité de recherche 12SP06, service de pneumologie, hôpital La Rabta, faculté de médecine de Tunis, université de Tunis El Manar, 1007 Tunis, Tunisie.
authors.forename: S
authors.initials: S
authors.lastname: Toujani
authors.affiliation: Unité de recherche 12SP06, service de pneumologie, hôpital La Rabta, faculté de médecine de Tunis, université de Tunis El Manar, 1007 Tunis, Tunisie.
authors.forename: H
authors.initials: H
authors.lastname: Snen
authors.affiliation: Service de pneumologie, hôpital Mongi Slim, faculté de médecine de Tunis, université de Tunis El Manar, Tunis, Tunisie.
authors.forename: N
authors.initials: N
authors.lastname: Ben Salah
authors.affiliation: Service de médecine préventive, faculté de médecine de Tunis, université de Tunis El Manar, Tunis, Tunisie.
authors.forename: A
authors.initials: A
authors.lastname: Ben Hmida
authors.affiliation: Service de pneumologie, hôpital Mongi Slim, faculté de médecine de Tunis, université de Tunis El Manar, Tunis, Tunisie.
authors.forename: B
authors.initials: B
authors.lastname: Louzir
authors.affiliation: Unité de recherche 12SP06, service de pneumologie, hôpital La Rabta, faculté de médecine de Tunis, université de Tunis El Manar, 1007 Tunis, Tunisie.
authors.forename: N
authors.initials: N
authors.lastname: Mhiri
authors.affiliation: Unité de recherche 12SP06, service de pneumologie, hôpital La Rabta, faculté de médecine de Tunis, université de Tunis El Manar, 1007 Tunis, Tunisie.
authors.forename: J
authors.initials: J
authors.lastname: Cherif
authors.affiliation: Unité de recherche 12SP06, service de pneumologie, hôpital La Rabta, faculté de médecine de Tunis, université de Tunis El Manar, 1007 Tunis, Tunisie.
authors.forename: M
authors.initials: M
authors.lastname: Beji
mesh_terms: D000328:Adult; D002940:Circadian Rhythm / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D017286:Polysomnography / Q000706:statistics & numerical data; D011446:Prospective Studies; D012720:Severity of Illness Index; D012890:Sleep / Q000502:physiology*; D020181:Sleep Apnea, Obstructive / Q000453:epidemiology / Q000473:pathology* / Q000503:physiopathology*
keywords: Apnoea-hypopnoea index; Index apnée-hypopnées; Obstructive sleep apnoea-hypopnoea syndrome; Polygraphie ventilatoire; Polysomnography; Syndrome d’apnée-hypopnée obstructive du sommeil