title: Validity and reliability of the Malay version of Sleep Apnea Quality of Life Index--preliminary results.
abstract: BACKGROUND
  The objective of this study was to determine the validity and reliability of the Malay translated Sleep Apnea Quality of Life Index (SAQLI) in patients with obstructive sleep apnea (OSA).
  
  
  METHODS
  In this cross sectional study, the Malay version of SAQLI was administered to 82 OSA patients seen at the OSA Clinic, Hospital Universiti Sains Malaysia prior to their treatment. Additionally, the patients were asked to complete the Malay version of Medical Outcomes Study Short Form (SF-36). Twenty-three patients completed the Malay version of SAQLI again after 1-2 weeks to assess its reliability.
  
  
  RESULTS
  Initial factor analysis of the 40-item Malay version of SAQLI resulted in four factors with eigenvalues >1. All items had factor loadings >0.5 but one of the factors was unstable with only two items. However, both items were maintained due to their high communalities and the analysis was repeated with a forced three factor solution. Variance accounted by the three factors was 78.17% with 9-18 items per factor. All items had primary loadings over 0.5 although the loadings were inconsistent with the proposed construct. The Cronbach's alpha values were very high for all domains, >0.90. The instrument was able to discriminate between patients with mild or moderate and severe OSA. The Malay version of SAQLI correlated positively with the SF-36. The intraclass correlation coefficients for all domains were >0.90.
  
  
  CONCLUSIONS
  In light of these preliminary observations, we concluded that the Malay version of SAQLI has a high degree of internal consistency and concurrent validity albeit demonstrating a slightly different construct than the original version. The responsiveness of the questionnaire to changes in health-related quality of life following OSA treatment is yet to be determined.
authors.forename: Norkhafizah
authors.initials: N
authors.lastname: Saddki
authors.forename: Hazama
authors.initials: H
authors.lastname: Mohamad
authors.forename: Nor Idayu
authors.initials: NI
authors.lastname: Mohd Yusof
authors.forename: Dasmawati
authors.initials: D
authors.lastname: Mohamad
authors.forename: Norehan
authors.initials: N
authors.lastname: Mokhtar
authors.forename: Wan Zaripah
authors.initials: WZ
authors.lastname: Wan Bakar
mesh_terms: D000328:Adult; D015992:Body Mass Index; D003430:Cross-Sectional Studies; D005163:Factor Analysis, Statistical; D005260:Female; D006305:Health Status Indicators; D006785:Hospitals, University; D006801:Humans; D007407:Interviews as Topic; D008296:Malaysia; D008297:Male; D008875:Middle Aged; D017063:Outcome Assessment, Health Care / Q000379:methods; D017286:Polysomnography; D011594:Psychometrics / Q000592:standards*; D011788:Quality of Life / Q000523:psychology*; D015203:Reproducibility of Results; D012647:Self-Assessment; D012720:Severity of Illness Index; D020181:Sleep Apnea, Obstructive / Q000175:diagnosis* / Q000208:ethnology / Q000628:therapy; D011795:Surveys and Questionnaires; D014175:Translating; D055815:Young Adult