title: Anxiety is associated with diminished exercise performance and quality of life in severe emphysema: a cross-sectional study.
abstract: BACKGROUND
  Anxiety in patients with chronic obstructive pulmonary disease (COPD) is associated with self-reported disability. The purpose of this study is to determine whether there is an association between anxiety and functional measures, quality of life and dyspnea.
  
  
  METHODS
  Data from 1828 patients with moderate to severe emphysema enrolled in the National Emphysema Treatment Trial (NETT), collected prior to rehabilitation and randomization, were used in linear regression models to test the association between anxiety symptoms, measured by the Spielberger State Trait Anxiety Inventory (STAI) and: (a) six-minute walk distance test (6 MWD), (b) cycle ergometry peak workload, (c) St. Georges Respiratory Questionnaire (SRGQ), and (d) UCSD Shortness of Breath Questionnaire (SOBQ), after controlling for potential confounders including age, gender, FEV1 (% predicted), DLCO (% predicted), and the Beck Depression Inventory (BDI).
  
  
  RESULTS
  Anxiety was significantly associated with worse functional capacity [6 MWD (B = -0.944, p < .001), ergometry peak workload (B = -.087, p = .04)], quality of life (B = .172, p < .001) and shortness of breath (B = .180, p < .001). Regression coefficients show that a 10 point increase in anxiety score is associated with a mean decrease in 6 MWD of 9 meters, a 1 Watt decrease in peak exercise workload, and an increase of almost 2 points on both the SGRQ and SOBQ.
  
  
  CONCLUSIONS
  In clinically stable patients with moderate to severe emphysema, anxiety is associated with worse exercise performance, quality of life and shortness of breath, after accounting for the influence of demographic and physiologic factors known to affect these outcomes.
  
  
  BACKGROUND
  ClinicalTrials.gov NCT00000606.
authors.affiliation: Mental Health Service, VA Ann Arbor Healthcare System, Ann Arbor, MI, USA. ngiardin@umich.edu
authors.forename: Nicholas D
authors.initials: ND
authors.lastname: Giardino
authors.forename: Jeffrey L
authors.initials: JL
authors.lastname: Curtis
authors.forename: Adin-Cristian
authors.initials: AC
authors.lastname: Andrei
authors.forename: Vincent S
authors.initials: VS
authors.lastname: Fan
authors.forename: Joshua O
authors.initials: JO
authors.lastname: Benditt
authors.forename: Mark
authors.initials: M
authors.lastname: Lyubkin
authors.forename: Keith
authors.initials: K
authors.lastname: Naunheim
authors.forename: Gerard
authors.initials: G
authors.lastname: Criner
authors.forename: Barry
authors.initials: B
authors.lastname: Make
authors.forename: Robert A
authors.initials: RA
authors.lastname: Wise
authors.forename: Susan K
authors.initials: SK
authors.lastname: Murray
authors.forename: Alfred P
authors.initials: AP
authors.lastname: Fishman
authors.forename: Frank C
authors.initials: FC
authors.lastname: Sciurba
authors.forename: Israel
authors.initials: I
authors.lastname: Liberzon
authors.forename: Fernando J
authors.initials: FJ
authors.lastname: Martinez
mesh_terms: D000368:Aged; D001007:Anxiety / Q000453:epidemiology* / Q000503:physiopathology*; D015897:Comorbidity; D003430:Cross-Sectional Studies; D004646:Emphysema / Q000453:epidemiology* / Q000503:physiopathology*; D017079:Exercise Tolerance; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D029424:Pulmonary Disease, Chronic Obstructive / Q000453:epidemiology* / Q000503:physiopathology*; D011788:Quality of Life; D018570:Risk Assessment; D012307:Risk Factors; D014481:United States