title: Difference between apnea-hypopnea index (AHI) and oxygen desaturation index (ODI): proportional increase associated with degree of obesity.
abstract: OBJECTIVE
  Obesity is one of the main predisposing factors for obstructive sleep apnea (OSA) hypopnea syndrome. It has been described that body mass index (BMI) influences the accuracy of oxygen desaturation index (ODI) for the diagnosis of OSA by polysomnography (PSG). We analyzed the relationship between traditional indicators: apnea-hypopnea index (AHI) and ODI in a population at high risk for OSA, by respiratory polygraphy (RP) and PSG.
  
  
  METHODS
  This is a retrospective study of 1898 patients with suspicion of OSA, from which 1053 underwent RP and 582 underwent PSG with OSA. We compared results considering gender, age, and degree of obesity.
  
  
  RESULTS
  This study included 1333 records of patients with OSA-more than 80 % of whom were overweight or obese. We observed that AHI and ODI increased progressively with obesity grade and said increase was associated with BMI only in men. The evaluation of the agreement between AHI and ODI found a difference between normal weight and obese patients, regardless of gender.
  
  
  CONCLUSIONS
  Study findings contribute to understand the role of oximetry in the diagnosis of OSA in obese patients. Our results were observed using full PSG and a simplified home method. The correlation between these indicators could improve our clinical interpretation of OSA severity among obese patients when abbreviated tests are used.
authors.affiliation: Hospital Británico, Perdriel 74, 1° Floor, CP 1280AEB, Buenos Aires, Argentina. glenda.uba@gmail.com.
authors.forename: G
authors.identifier: http://orcid.org/0000-0003-2772-8184
authors.initials: G
authors.lastname: Ernst
authors.affiliation: Hospital Británico, Perdriel 74, 1° Floor, CP 1280AEB, Buenos Aires, Argentina.
authors.forename: M
authors.initials: M
authors.lastname: Bosio
authors.affiliation: Hospital Británico, Perdriel 74, 1° Floor, CP 1280AEB, Buenos Aires, Argentina.
authors.forename: A
authors.initials: A
authors.lastname: Salvado
authors.affiliation: Hospital Alemán, Buenos Aires, Argentina.
authors.forename: E
authors.initials: E
authors.lastname: Dibur
authors.affiliation: Hospital Alemán, Buenos Aires, Argentina.
authors.forename: C
authors.initials: C
authors.lastname: Nigro
authors.affiliation: Hospital Británico, Perdriel 74, 1° Floor, CP 1280AEB, Buenos Aires, Argentina.
authors.forename: E
authors.initials: E
authors.lastname: Borsini
mesh_terms: D000328:Adult; D000368:Aged; D015992:Body Mass Index; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000097:blood* / Q000150:complications; D050177:Overweight / Q000097:blood* / Q000150:complications; D010100:Oxygen / Q000097:blood*; D017286:Polysomnography; D012189:Retrospective Studies; D012307:Risk Factors; D012737:Sex Factors; D020181:Sleep Apnea, Obstructive / Q000097:blood* / Q000209:etiology; D013223:Statistics as Topic
chemical_list: D010100:Oxygen
keywords: Obesity; Obstructive sleep apnea; Polysomonography; Respiratory polygraphy