Treated prevalence and incidence of dementia among National Health Insurance enrollees in Taiwan, 1996-2003.

The National Health Insurance database to determine the treated prevalence and incidence of dementia in Taiwan was used in this study. A population-based random sample of 22 118 subjects aged 65 or older was obtained as a dynamic cohort. Those study subjects who had filed at least one service claim from 1996 to 2003 for either outpatient care or inpatient care with a principal diagnosis of dementia were identified. The annual treated prevalence increased from 0.71% to 1.92% from 1996 to 2003. The annual treated incidence rates were around 0.76% to 1.04% per year from 1997 to 2003. The annual treated incidence rates for the 5-year age groups, from 65 to 90 years and older, were 0.44%, 0.65%, 0.98%, 1.46%, 1.81%, and 1.80%, respectively. Both the treated prevalence and incidence rates of dementia in National Health Insurance were lower than those of community studies.