In people with mild cognitive impairment, cholinesterase inhibitors do not prevent dementia

Cooper C, Li R, Lyketsos C, Livingston G. Treatment for mild cognitive impairment: systematic review. Br J Psychiatry. 2013;203:255-64.

Review question

In people with mild cognitive impairment, can treatment prevent dementia or improve cognitive function (e.g., thinking, learning, and remembering)?

Background

Mild cognitive impairment includes problems with thinking, memory, language, and judgment that are noticeable but don’t much affect daily living. Dementia is cognitive impairment that is serious enough to interfere with daily living.

How the review was done

The researchers did a systematic review, searching for studies that were published up to January 2013. They found 42 randomized controlled trials with 7803 patients.

The key features of the studies were as follows:

• All people had mild cognitive impairment.
• Treatments included cholinesterase inhibitors (e.g., donepezil, galantamine, or rivastigmine), nonsteroidal anti-inflammatory drugs (triflusal and rofecoxib), ginkgo biloba, vitamin E, B vitamins, omega-3 polyunsaturated fatty acids, exercise, group psychological therapy (e.g., memory training, relaxation, education), and computer-assisted cognitive training (e.g., matching sentences with pictures on computers).
• Treatments were usually compared with placebo.
• Outcomes were cognitive function and dementia.

What the researchers found

A summary of the main study outcomes is shown below. Results for the main outcomes of studies are usually more reliable than for other outcomes.

Treatments for preventing dementia

• Cholinesterase inhibitors, vitamin E, or gingko biloba did not prevent dementia.
• People taking rofecoxib were more likely to get dementia than those taking placebo.
• No studies looked at whether other treatments prevented dementia.

Treatments for improving cognitive function

• Cholinesterase inhibitors improved cognitive function by a small amount in 1 study but not in 2 other studies.
• Ginkgo biloba and 6 weeks of group psychological therapy each improved cognitive function, but the evidence was inconsistent or of low quality.
• Triflusal and B vitamins did not improve cognitive function.
• Moderate-intensity exercise did not improve cognitive function more than low-intensity exercise.
• Omega-3 polyunsaturated fatty acids, 6 months of group psychological therapy, and computer-assisted cognitive training were tested in only a small number of people.

Conclusion

In people with mild cognitive impairment, cholinesterase inhibitors do not prevent dementia. There isn’t enough evidence to know if other treatments affect dementia or cognitive function.

Treatments vs control (placebo, usual care, or no treatment) for mild cognitive impairment

*Compared with low-intensity exercise.