A five-year community-based longitudinal survival study of dementia in Beijing, China: a 10/66 Dementia Research Group population-based study

Background: Despite the magnitude of dementia, little research on survival duration and prognosis of dementia has been reported in developing countries. This study was conducted to investigate survival times, identify related prognostic factors and construct a prognostic index (PI) for community-based dementia patients in Beijing, China. Methods: This study is part of the 10/66 Dementia Research Group study in China. One hundred and thirty-seven dementia patients identified by 10/66 dementia criteria among 2162 participants and 137 referent subjects matched by age and sex were followed up for five years. Results: Ninety-one (66.4%) dementia patients and 51(37.2%) referent subjects died during the 5-year follow-up (p < 0.01). The median survival time of dementia patients was 4.2 years (95% CI: 3.8-4.6). Severity of dementia (severe/mild, HR: 8.765, 95% CI: 4.436-17.163), substantial disability (HR: 5.503, 95% CI: 3.017-8.135), co-morbidity (HR: 4.149, 95% CI: 2.254-7.736) and age (HR: 1.079, 95% CI: 1.048-1.110) were independent predictors of survival for patients with dementia. Using the PI calculated for each dementia patient, all dementia patients were classified into three groups: low, medium and high risk groups. The median survival times of each group were 5.2 years, 4.4 years and 1.5 years (p < 0.01), respectively. Conclusions: Survival times of community-based dementia patients were significantly shorter than those of referent subjects. Severity of dementia, substantial disability, co-morbidity and age were independent predictors of survival. The PI derived from the four predictors can stratify the mortality risk and predict life expectancy for community-dwelled dementia patients, although further validation is needed.