[Follow-up study on subjective quality of life for elderly persons with dementia using the Japanese version of Dementia Quality of Life Instrument (JDQoL)].

PURPOSE:There are few longitudinal studies on the subjective quality of life for elderly persons living in their own homes. The purpose of this study was to clarify the validity and reliability of the Japanese version of the Dementia Quality of Life Scale (JDQoL) used in a follow-up survey as part of a longitudinal study in Japan. METHODS:A baseline study was conducted from November 2002 to January 2003, and a year later a follow-up study was conducted from October 2003 to January 2004. The subjects included 72 (19 men and 53 women) elderly persons with dementia living in their own homes. Sixty-six were diagnosed with vascular dementia (VD) and 6 had senile dementia of Alzheimer's type (SDAT). The follow-up study included 60 subjects (VD: 56 and SDAT: 4); _10 of the original subjects were hospitalized, one died, and one was unable to attend daycare because of deterioration. Evaluation was conducted using the JDQoL, MiniMental State Examination (MMSE), and Geriatric Depression Scale (GDS). RESULTS:For the MMSE, the average score of the subjects in the follow-up study was 20.87 (+/- 4.80), which was significantly higher than the score of subjects that were excluded from the follow-up study (17.82 +/- 5.65). At baseline, reliability coefficient was demonstrated by Cronbach's alpha value of 0.744 approximately 0.886. One year later, Cronbach's alpha was 0.723 approximately 0.872. Among the subjects in the follow-up study, MMSE scores decreased significantly compared with the baseline study. In the subscales of the JDQoL, Negative Feelings (reversal item) significantly improved and Feeling of Belonging significantly decreased after one year (p<0.05). Each subscale of the JDQoL had significant correlation with the GDS at baseline and follow-up. Scores on the GDS at baseline had significant correlation with Self Esteem, Positive Feelings, Negative Feelings, and Feeling of Belonging of the JDQoL at follow-up (0.320 to 0.504; p<0.05). CONCLUSION:We demonstrated that the reliability and validity of the JDQoL was comparable to the English version of DQoL. Subjective QOL did not decline for all sub-scales, Negative Feelings in the JDQoL significantly improved compared to baseline.