Effects of rivastigmine on common symptomatology of Alzheimer's disease (EXPLORE).

Objective: To evaluate, in a real-world clinical setting, the efficacy of rivastigmine in the management of six symptoms commonly associated with Alzheimer's disease (AD).

Methods: This was a naturalistic, prospective, open-label, multi-centre, post-marketing, observational study. Data were collected by the participating study physicians at their practices across Canada. Subjects had a clinical diagnosis of mild-to-moderate AD and were prescribed rivastigmine by their treating physician. Efficacy was primarily evaluated by a physician-assessed, abbreviated Clinical Global Impression of Change (CGI-C) scale, focusing on six symptoms: attention, apathy, anxiety, agitation, irritability and sleep disturbance. Changes were assessed at months 3, 6 and 12. Several other patient-, physician- and caregiver-related assessments were also included.

Results: A total of 4460 patients were recruited by 353 study physicians; 3800 were deemed evaluable, having taken at least one dose of rivastigmine and with at least one post-baseline assessment. At baseline, attention problems were present in 86.0% of evaluable patients, anxiety in 77.3%, apathy in 68.3%, irritability in 64.0%, agitation in 54.6% and sleep disturbance in 54.5%. At both month 6 and month 12, for each symptom, the percentage of patients experiencing an improvement was considerably larger than the percentage of patients who experienced symptom worsening. Among evaluable patients, the proportions improving vs. deteriorating at month 6 were 46.4 vs. 8.8% for attention; 42.8 vs. 7.2% for apathy; 41.1 vs. 9.4% for anxiety; 33.8 vs. 7.7% for agitation; 35.1 vs. 10.1% for irritability; and 30.8 vs. 5.4% for sleep disturbance.

Limitations: Open-label studies have an inherent potential for bias by both the caregiver and the physician.

Conclusions: This study demonstrates that a considerable proportion of rivastigmine-treated patients experience improvements on each of the six symptoms studied. These findings add further support to previous randomised, clinical studies showing benefit of rivastigmine in AD.