Clinical InvestigationOutcomes, Health Policy, and Managed CareRelationships between changes in patient-reported health status and functional capacity in outpatients with heart failure
Section snippets
Methods
HF-ACTION was a multicenter, randomized controlled trial designed to test the long-term safety and efficacy of aerobic exercise training vs usual care in a large, multinational sample of patients with left ventricular dysfunction and heart failure.8 Enrollment criteria included left ventricular ejection fraction of 35% or less, New York Heart Association (NYHA) class II to IV heart failure, and ability and willingness to undergo exercise training. Patients were excluded if they were unable to
Results
Table I shows the baseline characteristics of the study population. Baseline characteristics did not differ by treatment group.18 Table II shows the visit-level missing data through 12 months of follow-up, accounting for patients who died or withdrew from the study.
Table III shows the Pearson correlation coefficients comparing changes in patient-reported health status and changes in the functional capacity measures at 3 and 12 months. After adjustment for baseline patient characteristics, there
Discussion
To our knowledge, ours is the first study to use longitudinal data to characterize relationships between changes in multiple aspects of patient-reported health status and changes in 2 commonly used functional measures of disease severity. The study population in HF-ACTION was large, relatively diverse, and balanced with respect to heart failure etiology, and the patients received evidence-based, guideline-supported therapy. We used a conservative approach to model these relationships and
Conclusions
Changes in patient-reported health status, as measured by the VAS and the KCCQ and its subscales, are not highly correlated with changes in functional capacity, including peak VO2 and 6-minute walk distance. According to the predominant model of patient outcomes,20 our findings do not alter the recommendation of considering a 5-point change in the KCCQ within individuals to be clinically meaningful.5 This information will help to inform researchers about study design and interpretation in heart
Disclosures
The authors are solely responsible for the design and conduct of this study, all study analyses, the drafting and editing of the manuscript, and its final contents. The content does not necessarily represent the official views of the National Heart, Lung, and Blood Institute or the National Institutes of Health. The relevant institutional review boards of the participating centers and the coordinating center approved the protocol. This work was supported by grants from the National Heart, Lung,
Acknowledgements
Stephen J. Ellis, PhD, Duke University, suggested consideration of alternative modeling approaches to estimate minimally important change. Damon M. Seils, MA, Duke University, assisted with the manuscript preparation. Dr Ellis and Mr Seils did not receive compensation for their assistance apart from their employment at the institution where the study was conducted.
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Leslee J. Shaw, PhD served as guest editor for this article.
Randomized controlled trial registration: clinicaltrials.gov identifier: NCT00047437.
Funding/support: HF-ACTION was funded by grants 5U01HL063747, 5U01HL066461, 5U01HL068973, 5U01HL066501, 5U01HL066482, 5U01HL064250, 5U01HL066494, 5U01HL064257, 5U01HL066497, 5U01HL068980, 5U01HL064265, 5U01HL066491, and 5U01HL064264 from the National Heart, Lung, and Blood Institute and grants R37AG018915 and P60AG010484 from the National Institute on Aging.