Background and Purpose There is no specific indicator for monitoring dementia management. We propose an auxiliary indicator called the community management rate, defined as the proportion of dementia patients who receive informal care from close caregivers or themselves within their community population. The 5-year community management rate is the percentage of dementia patients who are receiving community management at 5 years after they were diagnosed. The aim of this study was to identify how the community management rate has changed over time and how the 5-year community management rate differs according to age, sex, income, residence area, and comorbidities. Methods We analyzed customized research database of the Korean National Health Insurance Services from 2003 to 2018. The 5-year community management rate was calculated annually with newly diagnosed dementia patients, and compared among subgroups according to age, sex, income, residence area, and comorbidities. Results This study analyzed 549,297 patients. Among those newly diagnosed with dementia in 2003, the mean duration of community management during the 15-year follow-up was 5.98 years. The community management rate decreased rapidly from 2003 to 2006, after which it increased. A low 5-year community management rate was associated with older age, higher comorbidity burden, nonmetropolitan residence, and low income. Conclusions The community management rate seems to reflect diverse patient factors. Efforts are needed to reduce the comorbidity burden and differences in the 5-year community management rate according to residence area and income. This study indicates the need for further investigations into the use of this indicator to monitor the management of dementia patients.