Comparing the Characteristics of Patients With Newly Diagnosed Dementia Before and After 2008 in Seoul, South Korea: A Population-Based Study.

Abstract

Dear Editor, The burden of dementia is growing as the South Korean population ages.1 The South Korean government declared a “war on dementia” in 2008, and 25 dementia support centers (DSCs) were established between 2007 and 2009 in Seoul, South Korea. We previously reported that the dementia incidence in Seoul increased rapidly after 2007 and then stabilized after 2011.2 In the current study, we investigated the characteristics of patients with newly diagnosed dementia before and after 2008, and considered variables such as age, comorbidities, income, and dementia type. Using customized research data from the National Health Insurance Service (NHIS) database, data of patients with dementia diagnosed during 2005–2007 and 2009–2011 were analyzed and compared. We compared time periods between before the DSCs were established and those when dementia incidence increased rapidly after they were established. The data source and method of identifying patients with dementia have been described in detail previously.2 In brief, patients with dementia were defined by dementia-related diagnostic codes from the Korean Standard Classification of Diseases (F00, F01, F02, F03, G30, G31.00, G31.01, G31.02, G31.03, G31.04, and G31.82) or by the use of antidementia drugs (donepezil, galantamine, rivastigmine, and memantine). In order to only include patients with newly diagnosed dementia, those who had visited the hospital previously and were diagnosed with a dementia-related code were excluded. The International Classification of Diseases (ICD-10) version of the Charlson Comorbidity Index (CCI) was used.3,4 The patients were divided into groups according to age (six groups: 60–64, 65–69, 70–74, 75–79, 80–84, and ≥85 years old), sex, CCI (four groups: 0, 1, 2, and ≥3), income (quintiles), and dementia type (unspecified dementia [F03], Alzheimer’s disease dementia [F00, G30], vascular dementia [F01], and other [F02, G31.00–04, G31.82]). Patients with dementia who were first diagnosed during 2005–2007 or 2009–2011 were compared using t-test and chi-square test. This study evaluated 35,271 patients with incident dementia. The total number (age-adjusted incidence per 100,000 person-years) of patients with newly diagnosed dementia was 9,980 (273.21) during 2005–2007 and 25,291 (576.01) during 2009–2011 (p<0.0001). The age at first diagnosis increased from 76.45±7.64 years (mean±SD) to 77.89±7.78 years (p<0.0001). The percentage of females with dementia increased slightly from 67.02% to 67.11% (p<0.0001). A comparison of the patients who were diagnosed with dementia during 2005–2007 versus those diagnosed during 2009–2011 indicated significant differences between age groups (p<0.0001), CCI groups (p<0.001), income groups (p<0.0001), and dementia types (p<0.0001) (Fig. 1). Specifically, the proportions of patients aged ≥85 years, with a CCI of 0, in the lowest income group, and with unspecified dementia increased from 14.86% (n=6,689) to 21.29% (n=5,383) (Fig. 1A), from 76.33% (n=3,618) to 78.81% (n=19,932) (Fig. 1B), from 20.58% to Hyuk Sung Kwon Yong Whi Jeong Sojeong Park Dae Ryong Kang Hojin Choi