# A Systematic Literature Review of the Epidemiological, Diagnostic Workup, Humanistic, and Economic Burden of Alzheimer’s Disease in Spain

## TL;DR

This study reviews the impact of Alzheimer's disease in Spain, highlighting gaps in early diagnosis and the need for better data collection.

## Contribution

The paper provides a systematic review of Alzheimer's burden in Spain, emphasizing underdiagnosis and the need for standardized care strategies.

## Key findings

- Most studies focused on moderate-to-severe Alzheimer's with limited data on early stages.
- Informal caregivers, mostly women, experience significant declines in quality of life.
- Non-healthcare costs make up the majority of total expenditures related to Alzheimer's.

## Abstract

Introduction: Alzheimer’s disease (AD), the leading cause of dementia, affects over 700,000 individuals in Spain, with prevalence expected to rise due to population aging and improved diagnostic accuracy. Around 40,000 new cases are diagnosed annually, yet early-stage AD dementia remains underdiagnosed, limiting understanding of its full epidemiological, clinical, humanistic, and economic burden in Spain.

Methods: A systematic literature review (SLR) was conducted on the burden of AD dementia in Spain, focusing on observational studies published from January 2019 to January 2024. Searches were performed in PubMed/Medical Literature Analysis and Retrieval System Online (MEDLINE), Medicina en Español (MEDES), and Índice Bibliográfico Español en Ciencias de la Salud (IBECS), following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines.

Results: Twenty-six publications were included, mainly addressing moderate-to-severe AD dementia, with limited evidence on mild cognitive impairment (MCI) due to AD. Commonly used tools included the Mini-Mental State Examination (MMSE), Barthel Index, and Global Deterioration Scale (GDS). Neurologists were the primary clinicians involved in diagnosis (78.6%), though etiological diagnosis often lacked core AD biomarkers. Most caregivers were informal (mainly women), experiencing significant declines in health-related quality of life (HRQoL). Non-healthcare costs accounted for 84.6%-90.7% of total expenditures, followed by direct healthcare (6.1%-10.0%) and social care costs (2.8%-4.6%). Indirect costs, mostly from reduced working hours, represented 0.5%-0.8%.

Conclusions: This study highlights the need to improve early diagnosis of AD dementia and to establish reliable health registries to measure its burden. The lack of evidence on practice heterogeneity hinders standardized care strategies. Addressing these gaps is essential to improve patient management, ensure equitable access to timely and accurate diagnosis, and facilitate access to emerging disease-modifying treatments for AD dementia.