Does Treatment Response with Antidementia Drugs after 6 Months in Alzheimer's Disease Predict Long-term Treatment Outcome?

Background Alzheimer's disease (AD) is a chronic, progressive disorder that causes declines in cognitive and physical functions. This condition places severe burdens on families and caregivers. Delaying progressive declines in cognitive function and reducing their burden are thus important. Relationships between early treatment response and subsequent outcomes of schizophrenia and major depressive disorder have been reported. We thus aimed to investigate the relationships between treatment response to antidementia drugs in AD after 6 months (M) and subsequent outcomes. Methods Eligible individuals comprised 194 patients diagnosed with presumed AD. Of these, 110 patients who received antidementia drugs for the first time and were assessed using the Mini-Mental State Examination (MMSE) at 6 M, 12 M, and 24 M were categorized as responders (n = 84) or nonresponders (n = 26). Responders were defined as showing a change in MMSE after 6 M the same as or lower than that in the natural course according to previously reported data. Results No significant differences in baseline characteristics (age, sex, education, or comorbidities) were seen between groups. Mean MMSE score at baseline was significantly lower in responders (18.0) than in nonresponders (20.7; P = 0.008). Mean change from baseline MMSE was significantly smaller in responders than in nonresponders at both 12 M (-0.46 vs -2.5; P = 0.04) and 24 M (-0.78 vs -4.4; P = 0.001). Conclusions Treatment response with antidementia drugs after 6 M predicted better outcomes at 12 M and 24 M. Treatment response should be assessed every 6 M, and treatment should be reconsidered accordingly.