Lifetime expectancy and quality-adjusted life-year in Alzheimer's disease with and without cerebrovascular disease: effects of nursing home replacement and donepezil administration--a retrospective analysis in the Tajiri Project.

ABSTRACT

BACKGROUND: We previously demonstrated a positive correlation with nursing home (NH) replacement and donepezil (DNP) administration on lifetime expectancy after the onset of Alzheimer's disease (AD). However, the correlation with quality-adjusted life-year (QALY) remains to be elucidated, along with the additional impact of concomitant cerebrovascular disease (CVD). Based upon our recently reported health state utility values, we retrospectively analyzed the correlation with NH replacement and/or DNP administration on QALY and life expectancy in 'pure' AD (without CVD) and AD with CVD patients. METHODS: All outpatients at the Tajiri Clinic from 1999-2012 with available medical records and death certificates were included. The entry criteria were a dementia diagnosis (DSM-IV) and diagnoses of pure AD or AD with CVD (NINCDS-ADRDA), medical treatment for more than 3 months, and follow up to less than 1 year before death. The main outcomes were lifetime expectancy (months between the onset of dementia and death) and QALY. RESULTS: We identified 390 subjects, of whom 275 had the diagnosis of dementia that met the entry criteria, including 67 pure AD, 33 AD with CVD, and 110 VaD patients. For the AD patients, 52 had taken DNP and 48 had not received the drug due to treatment prior to the introduction of DNP in 1999 in Japan. For the pure AD group, there were positive correlation between NH and DNP and QALY, as well as lifetime expectancy. As for the AD with CVD group, only a correlation between DNP and lifetime expectancy was noted, with no correlation with QALY. CONCLUSIONS: We found positive correlations between DNP administration and NH replacement and lifetime expectancy and QALY after the onset of AD. However, concomitant CVD negated such a positive correlation with QALY. The findings suggest that QALY in AD is affected by CVD; thus, indicating the importance of CVD prevention.