Background:

Alzheimer’s disease (AD) is the most common type of dementia, causing progressive decline of memory, thinking, and behavior, impairing daily functioning. Early AD (eAD) includes mild cognitive impairment (MCI) due to AD and mild AD dementia.

Objective:

The aim of this study was to investigate symptomatic treatment prevalence and treatment patterns in eAD.

Methods:

Embase, MEDLINE, and EBM Reviews were searched in November 2021 for observational studies reporting symptomatic treatment patterns in eAD. The range of patients receiving treatment was collated. Risk of bias was assessed using the Joanna Briggs Institute (JBI) prevalence tool. Two independent reviewers screened the records, one performed data extraction and quality assessment while a second checked.

Results:

Twenty-one studies (prospective and retrospective cohorts, cross-sectional studies, and a survey) were included. Population size ranged from 23 to 2,028. Worldwide, 18 to 35% of patients diagnosed with MCI due to AD received any AChE inhibitor (three studies; n = 631), 7 to 8% memantine (two studies; n = 229), and 9% combination therapy (one study; n = 402). Patients receiving no treatment ranged from 41 to 54% (two studies; n = 733). Worldwide, in mild AD dementia patients, 13 to 89% received any AChE inhibitor (six studies; n = 3,715), 1 to 21% memantine (five studies, n = 3,527), and 0.4 to 39% combination therapy (four studies, n = 3,018). Patients receiving no treatment ranged from 9 to 26% (five studies, n = 4,073).

Conclusion:

Limitations in reporting led to unclear risk of bias. The results reveal a pattern of use of symptomatic treatment in eAD beyond approved labels and highlights the opportunity for new consensus guidelines to inform clinical practice.

PROSPERO registration: CRD42022296104.