How valid is the self-administered visual analogue scale for assessing the health status of elderly people?

The population of Japan is aging rapidly, and maintaining the quality of life of elderly people has become an important issue in contemporary Japan. This study was conducted to verify the validity of the self-administered visual analogue scale (VAS) for assessing the health status of elderly people. A survey was conducted in two villages in western Japan in 2003. A total of 2040 participants, aged between 60 and 75 years, completed questionnaires comprising the VAS and six Likert-type items for health status, physical strength, life enjoyment, appetite, sleep, and life satisfaction. Data of the valid participants who properly completed both the VAS and the Likert-type item on health status were analyzed (n=1579, 77.4%). Among the Likert-type items, the VAS score was the most associated with health status (r = 0.532), followed by physical strength (r = 0.509). The VAS score showed a weak negative correlation with age (r = -0.130), but no association with socioeconomic factors such as the number of family members or annual income. The correlations between the VAS and the Likert-type item on health status varied between categories in some attributes. Since the VAS score was moderately correlated with similar questions about health status in the Likert-type health questionnaire, it was considered that the VAS is a valid self-administered instrument for collecting data on the health status of elderly people. However, further investigations need to be conducted to improve the VAS and to establish better explanations for aged respondents.