Cognitive decline sensitivity by educational level and residential area: A descriptive study using long-term care insurance dementia registration data in South Korea

Abstract

In South Korea Long-Term Care Insurance (LTCI) system, the special dementia rating (SDR) is a registration grading for dementia patients who do not have a physical disability or functional restrictions and is the first applicable registration following the diagnosis of dementia. We investigated the differences in age of registration of SDR and age of dementia diagnosis according to the educational level and residential area. This was a retrospective, cross-sectional study using the Korean National Health Insurance Service dataset. Applications for SDR between July 2014 and December 2016 were identified for participant selection, and 32,352 patients with dementia were included. Educational levels were defined as follows: the illiterate, only-reading, 1 to 6 years, 6 to 12 years, and ≥12 years. Urban residents were those who lived in the city, as ascertained from the Korean administrative district system. The primary outcomes were ages at the time of dementia diagnosis and SDR registration. A lower education level significantly correlated with a higher proportion of older adults, but a higher number of years of education significantly increased with the proportion of males and urban residents (P < .001 for all). A higher education level was inversely associated with the age at diagnosis of dementia (P < .001) and at the registration of SDR (P < .001). Urban residents were diagnosed with dementia at a significantly lower age and registered for SDR earlier than rural residents (P < .001 for both). Both urban and rural residents consistently showed that a higher educational level was associated with lower age at the dementia diagnosis and SDR registration. Patients who were highly educated and living in urban areas were diagnosed with dementia and registered on SDR when they were relatively younger, indicating that cognitive decline sensitivity and medical accessibility are related to earlier dementia diagnosis and registration.