Abstract
BACKGROUND: Self-rated health (SRH) has in many population-based studies predicted adverse health outcomes, e.g. morbidity, permanent nursing home (NH) placement, and mortality. However, the predictive value of SRH to NH placement and mortality among elderly people is not consistent. This may be due to cognitive impairment. Since the SRH item is widely used, it is important to know whether SRH has different predictive value among people with cognitive impairments. We aimed to examine SRH and the risk of permanent NH placement and mortality among people with mild Alzheimer's disease (AD). METHODS: Data are from The Danish Alzheimer Intervention StudY (DAISY), a large randomized controlled trial of psychosocial intervention for patients with mild dementia and their caregivers with 3-years' follow-up. Five out of 14 Danish counties participated and 321 home-living elderly (mean age: 76.2 years) with mild AD (46.4 % male) were included during 2004 and 2005. Self-rated SRH, cognitive function (MMSE), quality of life (proxy-rated QOL-AD), activities of daily living (ADCS-ADL), insight, and socio-demographics were assessed at baseline. Comorbidities and information about NH placement and mortality was obtained over 3-years' follow-up from registries. With Cox proportional hazard regression we analysed the association between SRH (dichotomised into good vs. poor) and NH placement and mortality adjusted for potential confounders. RESULTS: At baseline 66 % reported excellent or good, and 34 % fair, poor or very poor SRH. Mean MMSE was 24.0 (range: 20-30). NH placement and mortality totalled 28.1 % and 16.5 % at 3-years' follow-up, respectively. Poor SRH at baseline was not related to increased risk of NH placement or to increased mortality neither in the univariable nor in multivariable analysis: In the fully adjusted models HR was 0.63 (95 % CI 0.38-1.05) and 1.28 (95 % CI 0.67-2.45), respectively. CONCLUSIONS: When poor SRH was present we found no increased risk for NH placement or death among elderly people with mild AD. SRH is a widely used parameter in clinical and epidemiological research but may not be a valid indicator of health in patients with AD due to loss of insight.