Clinical progression of moderate-to-severe Alzheimer's disease and caregiver burden: a 12-month multicenter prospective observational study

Background: Prospective studies on the clinical progression of Alzheimer's disease (AD) and its relationship to caregiver burden are needed to improve illness management and use of resources. Methods: This national, multicenter, observational study evaluated 1235 moderate to severe AD patients under routine care in Spain. Baseline cross-sectional sociodemographic and clinical data, and changes from baseline to month 12 of various neuropsychological tests and clinical ratings, including Blessed Dementia Scale, Mini-mental State Examination (MMSE), Hughes Clinical Dementia Rating sum-of-boxes (CDR-SB), Clinical Global Impression of Change (CGIC) and Zarit Caregiver Burden scales, were recorded and comprehensively analyzed. Results: Baseline data were in accordance with characteristics consistently reported to influence AD risk regarding anthropometrics, sociocultural features and comorbidities. Significant progressive functional impairments (i.e. in routine activities and essential daily tasks) and cognitive (i.e. MMSE and CDR-SB) impairments were found at month 12. However, patients' behavior and caregivers' burden improved slightly, but significantly, corroborating the major influence of behavioral symptoms on caregivers' distress. Caregivers showed significantly lower burden with patients with higher levels of education and, to a lesser extent, when patients received AD-specific medication. Physicians accurately detected AD clinical evolution as their CGIC ratings significantly correlated with all tests. Conclusions: These findings reinforce previous AD knowledge and add data on the clinical course of advanced stages of AD. Caregiver burden depended more on patients' behavioral alterations than on their functional or cognitive declines; and it was diminished by their patients having higher levels of education and being treated with AD-specific medications. Research into unexplored factors that might reduce caregiver burden, ultimately benefiting both patients and caregivers, is encouraged.