Potentially modifiable factors associated with agitation and aggression in Alzheimer's disease: results of the ICTUS study.

Objectives: To study potentially modifiable factors associated with the severity of agitation or aggression (A/A) symptoms among Alzheimer's disease (AD) patients.

Design: Data from the Impact of Cholinergic Treatment Use (ICTUS) study, European longitudinal prospective observational study.

Setting: Community dwelling outpatients included in 29 European memory clinics.

Participants: 1375 participants with probable AD (Mini-Mental State Examination score of 10-26) with an informal caregiver.

Measurements: At baseline and twice yearly over the two-year follow-up, patients underwent comprehensive clinical and neuropsychological assessments: sociodemographic data, cognitive status, functional impairment, and assessment of neuropsychiatric symptoms based on Neuro-Psychiatric Inventory (NPI). The ZARIT scale assessed the caregiver's burden. The variable of interest was the severity of the item of A/A of the NPI. To study factors associated to the severity of A/A symptoms six months later, a multivariate mixed regression model was used.

Results: Frequency of A/A symptom varied from 30% to 34% at each visit. Two factors were found to be independently associated with the severity of A/A: (1) the presence of affective disorder (anxiety, depression, and/or irritability) that increased the severity of the A/A by 0.89 point (coefficient:0.89; 95% Confidence Interval (CI) = [0.48,1.30], p < 0.001), and (2) a severe caregiver burden that increased the severity of the A/A by 1.08 point (coefficient:1.08; 95% CI = [0.69,1.47], p < 0.001).

Conclusion: Research should evaluate whether the identification and treatment of an affective disorder along with the evaluation and optimal management of the caregiver would have a positive impact on the course of A/A in mild to moderate AD patients.