Impact of nutritional status on the evolution of Alzheimer's disease and on response to acetylcholinesterase inhibitor treatment

Background: Weight loss is frequently observed in patients with Alzheimer's disease (AD), as observed in clinical practice and reported in the literature. However, information on the evolution of nutritional status and its impact on the prognosis of AD is still scarce. Objective: Our aim was to determine the impact of nutritional status on the evolution of AD and on the response to treatment with acetylcholinesterase inhibitors (AChEI) by prospective one-year follow-up of AD patients living at home. Methods: We studied a cohort of 523 patients with Alzheimer's disease referred from 1994 to 2002 to an Alzheimer centre. After diagnosis, they were followed for one year in a prospective observational study in clinical practice. At entry and every 6 months, patients underwent standardised neurocognitive and geriatric evaluation (MMSE, ADAS-cog, IADL, MNA, caregiver burden). These evaluations were accompanied by complete clinical examination, standard paraclinical investigations and recording of treatment received. Results: Of our patients, 25.8% presented at inclusion a risk of undernutrition with an MNA score of 23.5 or less. During follow-up, the number of patients with rapid loss on the MMSE (3 points or more in one year) was higher in subjects who presented a risk of undernutrition at inclusion (53.6%) than in well-nourished subjects (43.2%) (P = 0.07). Similarly, increased dependence at one year was more frequent in subjects at risk of undernutrition at inclusion (57.7% versus 44.4%, P = 0.0219). The beneficial effect of AChEI treatment on cognitive function was not influenced by initial nutritional status; on the contrary, among the subjects at risk of undernutrition at inclusion, the risk of rapid loss on the MMSE in one year was decreased in subjects treated during follow-up compared with untreated subjects (43.9% versus 73.1%; OR = 0.29: 95% CI = 0.10-0.83; P = 0.0219). This relationship was not found in subjects whose initial MNA score was greater than 23.5. Conclusion: Our work indicates that AD patients living at home with a caregiver are frequently at risk of undernutrition. Undernourished patients seem to present more rapid aggravation of the disease, but paradoxically, these patients appear to be those who best respond to AChEI treatment.