Exercise: Congestive heart failure

This website is for students following the M.Sc. in Evidence Based Practice at the University of York.

The following is the abstract of a paper:

A striking rise in the incidence and prevalence of congestive heart failure (CHF) in the Chinese population has been reported. While promoting the quality of life (QOL) of these patients is widely recognized as an important clinical priority, there is not a validated Chinese disease-specific QOL measure for CHF patients. The aim of this study was to validate the Chinese version of Chronic Heart Failure Questionnaire (CHQ-C) which measures the disease-specific QOL of patients with CHF. A sample of 110 CHF elderly patients and a comparison group of 64 healthy elderly people was recruited. Structured questionnaires were administered by a research nurse.

Criterion and construct validity of CHQ-C was demonstrated by its significant correlation with the New York Heart Association classification (Spearman r = -0.52, p < 0.001) and the Chinese version of Hospital Anxiety and Depression scale (Pearson r = -0.74, p < 0.001), respectively. Known-groups comparison also demonstrated the ability of CHQ-C to differentiate the QOL of people with or without CHF. Confirmatory factor analysis supported the original four-factor structure of CHQ. In terms of internal consistency and test-retest reliability, CHQ-C demonstrated a Cronbach's alpha of 0.95 and an intraclass correlation coefficient (ICC) of 0.75, respectively. The responsiveness coefficient of CHQ-C was 0.63.

In conclusion, CHQ-C is recommended as a valid and reliable tool for evaluating the QOL of Chinese patients with CHF.

(Source: Lee DTF, Yu DSF, Woo J. Validation of the Chronic Heart Failure Questionnaire (Chinese version). Quality of Life Research 2005; 14: 1421-1426.)

The New York Heart Association classification is widely-used by cardiologists. Patients’ severity of heart disease is recorded in four ordered categories, class IV being the most severe:

Class I: patients with no limitation of activities; they suffer no symptoms from ordinary activities.
Class II: patients with slight, mild limitation of activity; they are comfortable with rest or with mild exertion.
Class III: patients with marked limitation of activity; they are comfortable only at rest.
Class IV: patients who should be at complete rest, confined to bed or chair; any physical activity brings on discomfort and symptoms occur at rest.

(http://www.hcoa.org/hcoacme/chf-cme/chf00070.htm)

Questions about this abstract:

What is the difference between criterion validity and construct validity?
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How does a negative correlation between CHQ-C and NYHA provide evidence for criterion validity?
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How does a negative correlation between CHQ-C and HADS provide evidence for construct validity?
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‘Known-groups comparison also demonstrated the ability of CHQ-C to differentiate the QOL of people with or without CHF.’ What type of validity does this show?
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In terms of internal consistency, CHQ-C demonstrated a Cronbach's alpha of 0.95. What is Cronbach's alpha and how would alpha = 0.95 be interpreted?
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In terms of test - retest reliability, CHQ-C demonstrated intraclass correlation coefficient (ICC) of 0.75. What is meant by ‘test-retest reliability’, and how does the intraclass correlation coefficient measure it?
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Last updated: 5 March, 2007