title: Fatigue and sleepiness determine respiratory quality of life among veterans evaluated for sleep apnea.
abstract: BACKGROUND
  In those with symptoms indicative of obstructive sleep apnea (OSA), respiratory-specific health-related quality of life (HRQL) may be an important patient-centered outcome. The aim of this study was to assess the associations between sleepiness, fatigue, and impaired general and respiratory-specific HRQL among persons with suspected OSA.
  
  
  METHODS
  We evaluated military veterans consecutively referred for suspected OSA with sleep studies yielding apnea-hypopnea index (AHI) values. They also completed the sleepiness (Epworth Sleepiness Scale [ESS]), and fatigue (Fatigue Severity Scale [FSS]) questionnaires, as well as two HRQL instruments (the generic Short-Form SF-12v2 yielding the Physical Component Scale [PCS] and the respiratory-specific Airways Questionnaire [AQ]-20R). Multiple linear regression tested the associations between ESS and FSS (standardized as Z scores for scaling comparability) with AQ-20R, accounting for AHI, SF-12v2-PCS and comorbid respiratory conditions other than OSA.
  
  
  RESULTS
  We studied 1578 veterans (median age 61.1 [IQR 16.8] years; 93.9% males). Of these, 823 (52%) met AHI criteria for moderate to severe OSA (AHI ≥15/h). The majority reported excessive daytime sleepiness (53%; median ESS 11 [IQR 9]) or fatigue (61%; median FSS 42 [IQR 23]). The median AQ-20R was 4 [IQR 1-8]. Controlling for AHI, SF-12v2-PCS, respiratory co-morbid conditions, body mass index, and demographics, both ESS and FSS were significantly associated with poorer AQ-20R: for each; ESS, 1.6 points (95% CI 1.4-1.9), and for FSS, 2.5 points (95% CI, 2.3-2.7).
  
  
  CONCLUSIONS
  Greater daytime sleepiness and fatigue are associated with poorer respiratory-specific HRQL, over and above the effects of OSA, respiratory comorbidity, and generic physical HRQL.
authors.affiliation: Department of Internal Medicine, Occupational Diseases and Hematology, Kyrgyz State Medical Academy, Bishkek, Kyrgyzstan. denisvinnikov@mail.ru.|School of Public Health, Al-Farabi Kazakh National University, Almaty, Kazakhstan. denisvinnikov@mail.ru.
authors.forename: Denis
authors.identifier: http://orcid.org/0000-0003-0991-6237
authors.initials: D
authors.lastname: Vinnikov
authors.affiliation: Division of Occupational and Environmental Medicine, Department of Medicine, University of California, San Francisco, San Francisco, CA, USA.|SF Veterans Affairs Medical Center, San Francisco, CA, USA.
authors.forename: Paul D
authors.initials: PD
authors.lastname: Blanc
authors.affiliation: Pulmonary, Critical Care and Sleep Medicine Section, VA Palo Alto Health Care System, Palo Alto, CA, USA.
authors.forename: Alaena
authors.initials: A
authors.lastname: Alilin
authors.affiliation: Starling Physicians, New Britain, CT, USA.
authors.forename: Moshe
authors.initials: M
authors.lastname: Zutler
authors.affiliation: Pulmonary, Critical Care and Sleep Medicine Section, VA Palo Alto Health Care System, Palo Alto, CA, USA.|Division of Pulmonary and Critical Care Medicine, Department of Medicine, Stanford University, Palo Alto, CA, USA.|Center for Health Policy (CHP/PCOR), Stanford University, Palo Alto, CA, USA.
authors.forename: Jon-Erik C
authors.initials: JC
authors.lastname: Holty
mesh_terms: D000328:Adult; D000368:Aged; D015897:Comorbidity; D005221:Fatigue / Q000453:epidemiology / Q000523:psychology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D017286:Polysomnography; D011788:Quality of Life / Q000523:psychology*; D020181:Sleep Apnea, Obstructive / Q000453:epidemiology / Q000523:psychology*; D011795:Surveys and Questionnaires; D014728:Veterans / Q000523:psychology* / Q000706:statistics & numerical data
keywords: Asthma; Chronic obstructive; Disorders of excessive somnolence; Fatigue; Health status indicators; Lung diseases; Pulmonary disease; Quality of life; Sleep apnea syndromes