Cognitive changes under memantine according to vitamin D status in Alzheimer patients: An exposed/unexposed cohort pilot study.

Memantine is a symptomatic treatment that partially prevents cognitive decline in Alzheimer disease (AD). The neuroprotective effects of memantine and vitamin D may potentiate each other, with benefits for cognition. The objective of this exposed/unexposed pilot study was to determine the cognitive changes among AD patients using memantine according to the presence or absence of vitamin D deficiency (VDD). Fifty-eight AD patients followed in a memory clinic during 6 months between 2009 and 2014 (mean±standard deviation, 82.9±5.0years; 56.9%female) were separated into four groups according to VDD (i.e., serum 25-hydroxyvitamin D≤25nM) at M0 and M6 (i.e., Group 1: no VDD-M0, no VDD-M6; Group 2: VDD-M0, no VDD-M6; Group 3: no VDD-M0, VDD-M6; Group 4: VDD-M0, VDD-M6). The 6-month cognitive change was examined with the Mini-Mental State Examination (MMSE) score in the 4 groups according to the use of memantine. Age, gender, body mass index, IADL score, GDS score, and use of pchychoactive drugs were measured at baseline. We found that participants using memantine had a lower MMSE score at M0 compared to those without memantine (P=0.006). After 6 months of follow-up, there was a memantine-related improvement of the MMSE score only in the participants with VDD-M6. This was significant in Group 3 with no VDD-M0 (P=0.039), but not in Group 4 who already had VDD-M0. Similarly, using memantine was associated with a 6-month improvement of MMSE only in Group 3 in whom VDD appeared during the follow-up (β=8.8, P=0.044). In conclusion, the use of memantine was associated with improved cognitive performance after 6 months of treatment in the presence of VDD at M6. Memantine may prevent the cognitive decline that accompanies the onset of VDD, which prompts to give to AD patients a regimen combining both memantine and vitamin D supplements.