Abstract
PURPOSE: Evidence supports the use of waist circumference (WC) as an important clinical measure of body composition and obesity-related health risk. Self-monitoring of WC may be problematic for older persons, especially for those with a chronic illness such as heart failure (HF). No studies to date have measured the accuracy of self-measured WC in older persons with HF. Therefore, the objective of this study was to determine the reliability and validity of self-measured WC in older patients with HF.
METHODS: The reliability of self-measured WC was evaluated over 7 days in 100 older (65-93 years) men and women with HF. The validity and accuracy of self-measured WC in comparison with technician-measured WC was evaluated in a second group of 45 men and women (40-91 years) recruited from a HF clinic.
RESULTS: Reliability results identified a high intraclass correlation between the 7 self-measurements (r = 0.99, P < .0001). The validity analysis yielded a correlation of 0.98 between self- and technician-measured WC (P < .0001). Mean differences between technician- and self-measurement were insignificant (0.60 cm; 95% CI: -0.35-1.50). Limits of agreement were -5.5 to 6.7 cm and indicated no systematic differences between self- and technician-measured WC. Ninety-six percent of participants were able to correctly classify themselves into the appropriate WC risk category.
CONCLUSIONS: Results indicate that a single self-measurement of WC is reliable. Validation results indicate that WC self-measured by older HF patients may be appropriate for large epidemiologic studies. However, the large limits of agreement suggest that self-measured WC may not be adequately sensitive for monitoring individual changes.