Clinical Benefits of Rivastigmine in the Real World Dementia Clinics of the Okayama Rivastigmine Study (ORS)

Background/Objective: Alzheimer's disease (AD) is one of the most important diseases in an aging society, but the clinical effects of rivastigmine have not been fully examined in real world domestic clinics. Methods: We performed the "Okayama Rivastigmine Study (ORS)" to retrospectively analyze the clinical effects of rivastigmine (n=75) or donepezil (n=71) on AD patients with seven dementia assessment batteries at the baseline, 3, 6, and 12 months. In addition, we divided the rivastigmine group into two subgroups at the baseline: the mild behavioral and psychological symptoms of dementia (BPSD) group (Abe's BPSD score (ABS) <6) and the severe BPSD group (6≤ABS). In these two subgroups, baseline scores and changes were also retrospectively analyzed until 12 months. Results: Rivastigmine significantly improved the Mini-Mental State Examination score at 3 months (∗p< 0.05 versus baseline) and at 6 months (∗p< 0.05), the Frontal Assessment Battery (FAB) at 6 months (∗p< 0.05), and ABS at 3 months (∗∗p< 0.01) while donepezil only stabilized the three cognitive scores. On the other hand, the Geriatric Depression Scale and the Apathy Scale were stable until 12 months in both groups. Baseline BPSD severity-dependent analysis showed a small improvement of FAB at 6 months in the mild BPSD subgroup (∗p< 0.05) and a great improvement of ABS at 3 months in the severe BPSD subgroup (∗∗p< 0.01) in the rivastigmine group. Conclusions: Our present study showed that rivastigmine improved both cognitive and affective functions at 3 and 6 months, and suggested an advantage at 3 and 6 months compared to donepezil in real world dementia clinics.