title: Relationships between changes in patient-reported health status and functional capacity in outpatients with heart failure.
abstract: BACKGROUND
  Heart failure trials use a variety of measures of functional capacity and quality of life. Lack of formal assessments of the relationships between changes in multiple aspects of patient-reported health status and measures of functional capacity over time limits the ability to compare results across studies.
  
  
  METHODS
  Using data from HF-ACTION (N = 2331), we used the Pearson correlation coefficients and predicted change scores from linear mixed-effects modeling to demonstrate the associations between changes in patient-reported health status measured with the EQ-5D visual analog scale and the Kansas City Cardiomyopathy Questionnaire (KCCQ) and changes in peak VO(2) and 6-minute walk distance at 3 and 12 months. We examined a 5-point change in KCCQ within individuals to provide a framework for interpreting changes in these measures.
  
  
  RESULTS
  After adjustment for baseline characteristics, correlations between changes in the visual analog scale and changes in peak VO(2) and 6-minute walk distance ranged from 0.13 to 0.28, and correlations between changes in the KCCQ overall and subscale scores and changes in peak VO(2) and 6-minute walk distance ranged from 0.18 to 0.34. A 5-point change in KCCQ was associated with a 2.50-mL kg(-1) min(-1) change in peak VO(2) (95% CI 2.21-2.86) and a 112-m change in 6-minute walk distance (95% CI 96-134).
  
  
  CONCLUSIONS
  Changes in patient-reported health status are not highly correlated with changes in functional capacity. Our findings generally support the current practice of considering a 5-point change in the KCCQ within individuals to be clinically meaningful.
authors.affiliation: Duke Clinical Research Institute, Duke University School of Medicine, Durham, NC, USA. kathryn.flynn@duke.edu
authors.forename: Kathryn E
authors.initials: KE
authors.lastname: Flynn
authors.forename: Li
authors.initials: L
authors.lastname: Lin
authors.forename: Gordon W
authors.initials: GW
authors.lastname: Moe
authors.forename: Jonathan G
authors.initials: JG
authors.lastname: Howlett
authors.forename: Lawrence J
authors.initials: LJ
authors.lastname: Fine
authors.forename: John A
authors.initials: JA
authors.lastname: Spertus
authors.forename: Timothy R
authors.initials: TR
authors.lastname: McConnell
authors.forename: Ileana L
authors.initials: IL
authors.lastname: Piña
authors.forename: Kevin P
authors.initials: KP
authors.lastname: Weinfurt
mesh_terms: D000368:Aged; D005260:Female; D006304:Health Status; D006333:Heart Failure / Q000503:physiopathology*; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D010147:Pain Measurement; D011788:Quality of Life; D016032:Randomized Controlled Trials as Topic; D057566:Self Report; D012720:Severity of Illness Index; D013318:Stroke Volume