Background COVID-19 outbreak has led to severe health burden in the elderly. Age, morbidity and dementia have been associated with adverse outcome. Aims To evaluate the impact of COVID-19 on health status in home-dwelling patients. Methods 848 home-dwelling outpatients with dementia contacted from April 27 to 30 and evaluated by a semi-structured interview to evaluate possible health complication due to COVID-19 from February 21 to April 30. Age, sex, education, clinical characteristics (including diagnosis of dementia) and flu vaccination history were obtained from previous medical records. Items regarding change in health status and outcome since the onset of the outbreak were collected. COVID-19 was diagnosed in patients who developed symptoms according to WHO criteria or tested positive at nasal/throat swab if hospitalized. Unplanned hospitalization, institutionalization and mortality were recorded. Results Patients were 79.7 years old (SD 7.1) and 63.1% were females. Ninety-five (11.2%) patients developed COVID-19-like symptoms. Non COVID-19 and COVID-19 patients differed for frequency of diabetes (18.5% vs. 37.9%, p < 0.001), COPD (7.3% vs. 18.9%,p < 0.001), and previous flu vaccination (56.7% vs. 37.9%,p < 0.001). Diabetes and COPD were positively associated with COVID-19, whereas higher dementia severity and flu vaccination showed an inverse association. Among COVID-19 patients, 42 (44.2%) were hospitalized while 32 (33.7%) died. Non COVID-19 patients' hospitalization and mortality rate were 1.9% and 1.2%, respectively. COVID-19 and COPD were significantly associated with the rate of mortality. Discussion/conclusions A high proportion of adverse outcome related to COVID-19 was observed in home-dwelling elderly patients with dementia. Active monitoring though telehealth programs would be useful particularly for those at highest risk of developing COVID-19 and its adverse outcomes.