Objective: To study the predictive factors on mortality and survival of elderly dementia in Shanghai.
Methods: Subjects were from people who had been screened in a prevalence survey study from the selected 5 urban and 4 rural communities from 1997 to 1998. Phase I screening was carried out by a brief memory testing with mini-mental state examination. In phase II, those who scored below the cutoff points and 4% of those whose score was in the normal range were interviewed to identify dementia through a set of diagnostic examinations according to the DSM IV criteria. In phase III which was six months later, a follow-up program was conducted for all persons who were involved in phase II to identify those with Alzheimer's dementia (AD) and vascular dementia (VaD) according to NINCDS-ADRDA and NINDA-AIREN criteria and other types of dementia.
Results: The mortality of elderly dementia was 6.06/1000 person-years. Compared to nondementia group, the survival rate of dementia group had a decrease of 57% after 40 months of follow-up (P < 0.05). There was no statistical difference between AD and VaD groups. The relative risk of death caused by dementia, AD and VaD were 1.63 (95% CI: 1.42-1.86), 1.71 (95% CI: 1.44-2.03) and 1.45 (95% CI: 1.16-1.82), respectively. Some factors such as age (RR = 1.0685), severalty (RR = 1.5733), and high ADL (RR = 1.0368) might have increased the risk of death among those patients.
Conclusion: The mortality of elderly dementia in Shanghai was lower than that seen in other areas in the world. There was no obvious difference between the survival rates of AD and VaD patients. Age, severalty and high ADL seemed to be the risk factors to the death outcome.