Outcomes, health policy, and managed care: relationships between patient-reported outcome measures and clinical measures in outpatients with heart failure.
BACKGROUND
Patient-reported outcomes are increasingly used to assess the efficacy of new treatments. Understanding relationships between these and clinical measures can facilitate their interpretation. We examined associations between patient-reported measures of health-related quality of life and clinical indicators of disease severity in a large, heterogeneous sample of patients with heart failure.


METHODS
Patient-reported measures, including the Kansas City Cardiomyopathy Questionnaire (KCCQ) and the EuroQol Visual Analog Scale (VAS), and clinical measures, including peak VO(2), 6-minute walk distance, and New York Heart Association (NYHA) class, were assessed at baseline in 2331 patients with heart failure. We used general linear models to regress patient-reported measures on each clinical measure. Final models included for significant sociodemographic variables and 2-way interactions.


RESULTS
The KCCQ was correlated with peak VO(2) (r = .21) and 6-minute walk distance (r = .27). The VAS was correlated with peak VO(2) (r = .09) and 6-minute walk distance (r = .11). Using the KCCQ as the response variable, a 1-SD difference in peak Vo(2) (4.7 mL/kg/min) was associated with a 2.86-point difference in the VAS (95% CI, 1.98-3.74) and a 4.75-point difference in the KCCQ (95% CI, 3.78-5.72). A 1-SD difference in 6-minute walk distance (105 m) was associated with a 2.78-point difference in the VAS (95% CI, 1.92-3.64) and a 5.92-point difference in the KCCQ (95% CI, 4.98-6.87); NYHA class III was associated with an 8.26-point lower VAS (95% CI, 6.59-9.93) and a 12.73-point lower KCCQ (95% CI, 10.92-14.53) than NYHA class II.


CONCLUSIONS
These data may inform deliberations about how to best measure benefits of heart failure interventions, and they generally support the practice of considering a 5-point difference on the KCCQ and a 3-point difference on the VAS to be clinically meaningful.
Center for Clinical and Genetic Economics, Duke Clinical Research Institute, Duke University School of Medicine, Durham, NC 27715, USA. kathryn.flynn@duke.edu
Kathryn E
KE
Flynn
Li
L
Lin
Stephen J
SJ
Ellis
Stuart D
SD
Russell
John A
JA
Spertus
David J
DJ
Whellan
Ileana L
IL
Piña
Lawrence J
LJ
Fine
Kevin A
KA
Schulman
Kevin P
KP
Weinfurt
D000553:Ambulatory Care / Q000592:standards; D001294:Attitude to Health; D005080:Exercise Test / Q000706:statistics & numerical data; D017079:Exercise Tolerance; D005260:Female; D006291:Health Policy; D006304:Health Status; D006333:Heart Failure / Q000175:diagnosis* / Q000503:physiopathology / Q000628:therapy*; D006801:Humans; D008297:Male; D008329:Managed Care Programs / Q000592:standards; D008875:Middle Aged; D017063:Outcome Assessment, Health Care / Q000706:statistics & numerical data; D010101:Oxygen Consumption / Q000502:physiology; D011379:Prognosis; D011788:Quality of Life; D011795:Surveys and Questionnaires; D018487:Ventricular Dysfunction, Left / Q000175:diagnosis / Q000503:physiopathology / Q000628:therapy