Does cognitive impairment influence burden in caregivers of patients with Alzheimer's disease?

Alzheimer's disease (AD) is characterized by a progressive deterioration of various cognitive and behavioral abilities, and it also has a health impact on the patients' caregiver. Our aim was to determine the patient (and to a lesser extent the caregiver) characteristics that contribute most to the caregiver burden. We used the baseline data from the ICTUS study, a European longitudinal cohort of patients with mild to moderate AD. Data from 1091 patients and their caregivers was used for analysis. Three principal components analyses were performed on variables from the domains of cognition, neuropsychiatric symptoms, and daily function using the MMSE plus the ADAS-Cog, NPI, and IADL subscores, respectively. These were followed by a stepwise logistic regression to identify patient characteristics which best predict caregiver burden. The regression model (R2 = 0.35, p < 0.001) shows that the best explanatory variables are: 1) neuropsychiatric symptoms (NPI); 2) difficulties in the IADL; 3) time taken by caregiving; 4) demographic variables such as caregiver's age and patient sex; and 5) severity of cognitive impairment. In conclusion, our results demonstrate that although the strongest determinant of the caregiver burden is behavioral disturbance, the impact of the degree of cognitive impairment on burden is also significant.