High-dose vitamin E significantly slowed functional decline over two years in a population of patients with mild-moderate Alzheimer’s disease. Compared with placebo, 2,000 IU daily vitamin E reduced progression by 19% per year, colleagues wrote.
Patients, who took vitamin E scored about three units higher on a measure of daily function, wrote the Minneapolis Veterans Affairs Health Care System. A loss of this magnitude could translate into either the complete loss of being able to dress or bathe independently, or losing independence on any three different activities of daily living.
Vitamin E also proved better than memantine at delaying progression, although the difference was not statistically significant. But paradoxically, the combination of vitamin E and memantine was significantly less helpful than either intervention alone.
The four-year study randomized 613 patients with mild-moderate Alzheimer’s into four treatment groups: 2,000 lU/day of vitamin E, 20mg/day memantine, a combination of both, or placebo.
The primary outcome was change on the Alzheimer’s Disease Cooperative Study/Activities of Daily Living Inventory. Secondary endpoints included the Caregiver Activity Survey, a measure of the time care gives spend assisting Alzheimer’s patients.
The patients were a mean of 79 years old; 97% were men. The mean baseline score on the ADCS-ADL was 57 on a scale of 0-78, with lower numbers representing worse function.
The final analysis contained data on 561 patients. The dropout rate was similar between the groups; most of it was from death during the study. Only three withdrew from medication-related adverse events.
The mean follow-up time was just over 2 years. The mean decline on the ACDS-ADL from baseline was 3.15 units less than the decline in the placebo group. “The treatment effect translates into a clinically meaningful delay in progression in the [vitamin E group] of 6.2 months,” the investigators wrote. “A delay in progression was sustained throughout most of the trial, with delays at 1,2,3, and 4 years of 10.6, 8.7, 9.3, and 1.8 months, respectively.”
The placebo group also declined more than both the memantine and combination groups, but those differences were not statistically significant.
However, there was a significant negative treatment interaction between vitamin E and memantine, with patients who took the combination performing worse than patients taking either of the interventions alone.
There were no between-group differences in the rate of cognitive decline or neuropsychiatric symptoms. Patients in the vitamin E group did require about 2 hours less of caregiver time per day, compared with those on memantine, but that difference was not statistically significant, with a confidence interval of 0.63-3.71.
Despite being statistically not significant, the authors said the reduction in caregiver time was clinically meaningful and could have “a major effect on informal and direct medical costs .... The loss of the ability to perform ADLs is associated not only with increased caregiver burden, but also with nursing home placement,” the investigators noted.