Background Emergency room (ER) re‐hospitalizations are prevalent in severe Alzheimer's disease affected older patients. Design Quasi‐experimental before and after study. Setting Discharge of severely demented patients from a Special Alzheimer Acute Care Unit. Participants A total of 390 patients hospitalized in the unit from 2007 through 2009, with at least one of the following characteristics: severe disruptive behavioral and psychological symptoms of dementia (BPSD) (agitation, aggressiveness, and psychotic symptoms), change of living arrangement related to BPSD, exhaustion of the principal caregiver, and discharge of a subject with anosognosia living alone in the community. Intervention The intervention consisted of an individualized care plan, targeting the problems observed during the hospital stay, implemented by the means of regular telephone contacts (in the first week after discharge, before the end of the first month, and then at 3 and 6 months) between a geriatric team and the patient's caregiver. Information was gathered on functional decline, BPSD, change of living arrangement and treatment. The calls were followed by a telephone intervention providing advice, support, and information to the caregiver. When required, these calls were followed by a consultation with a physician or psychologist, or by a consultation in the patient's home. Measurements The primary outcome measure was the ER re‐hospitalization rate, defined as occurring within 31 days of discharge. Results The early ER re‐hospitalization rate was 8.39% in 2007 versus 8.02% in 2008 (p = 0.818) and 7.47% in 2009 (p = 0.563). Vocal disruptive behavior are more prevalent in re‐hospitalized patients (9.64% versus 3.97%, p = 0.05) than in non re‐hospitalized patients. Conclusion We found a nonsignificant decrease of early ER re‐hospitalization rate at 1 month after discharge. Interventions addressing severe dementia affected patients with BPSD are needed, as this is a major issue in the organization of health care systems. Copyright © 2013 John Wiley & Sons, Ltd.