Application of capture-recapture methodology to estimate the prevalence of dementia in South Carolina

PURPOSE: The purpose of this study was to estimate the prevalence of dementia in individuals 65 years of age and older in the state of South Carolina using capture-recapture methodology. METHODS: We linked data from the Department of Mental Health admissions, inpatient admissions, and emergency room visits. Separate log-linear models were used to obtain estimates of the underascertainment-corrected prevalence of dementia in twelve age-gender-race subgroups, which were summed to estimate the prevalence of dementia in the total population. RESULTS: We found an overall prevalence of dementia of 14% in South Carolina for persons 65 years of age and older using capture-recapture methodology. This estimate of persons with dementia is 25% higher than the identified cases of dementia in the South Carolina Alzheimer's Disease Registry (10.5%). CONCLUSIONS: Although capture-recapture methods are prone to limitations, they can be used to more accurately estimate the prevalence of dementia in a geographic area.