Reproducibility and responsiveness of quality of life assessment and six minute walk test in elderly heart failure patients

Objective - To examine the reproducibility and responsiveness to change of a six minute walk test and a quality of life measure in elderly patients with heart failure. Design - Longitudinal within patient study. Subjects - 60 patients with heart failure (mean age 82 years) attending a geriatric outpatient clinic, 45 of whom underwent a repeat assessment three to eight weeks later. Main outcome measures - Subjects underwent a standardised six minute walk test and completed the chronic heart failure questionnaire (CHQ), a heart failure specific quality of life questionnaire. Intraclass correlation coefficients (ICC) were calculated using a random effects one way analysis of variance as a measure of reproducibility. Guyatt's responsiveness coefficient and effect sizes were calculated as measures of responsiveness to change. Results - 24 patients reported no major change in cardiac status, while seven had deteriorated and 14 had improved between the two clinic visits. Reproducibility was satisfactory (ICG > 0.75) for the six minute walk test, for the total CHQ score, and for the dyspnoea, fatigue, and emotion domains of the CHQ. Effect sizes for all measures were large (> 0.8), and responsiveness coefficients were very satisfactory (> 0.7). Effect sizes for detecting deterioration were greater than those for detecting improvement. Conclusions - Quality of life assessment and a six minute walk test are reproducible and responsive measures of cardiac status in frail, very elderly patients with heart failure.