Global burden, quality of care, and cross-country inequalities in Alzheimer's disease and other dementias from 1990 to 2021.

Background: As global populations age, the burden of dementia increases, raising challenges for healthcare systems. Care quality is key to supporting individuals with dementia, but few studies have assessed this at a global level. We aimed to assess the burden and care quality of Alzheimer's disease and related dementias (ADRDs) and cross-country inequalities between 1990 and 2021.

Methods: We conducted a secondary analysis of the Global Burden of Diseases Study (GBD) 2021, focussing on disability-adjusted life-years (DALYs) and care quality (measured by a variational autoencoder-based Quality of Care Index (QCI-v), range = 1-100) of ADRDs. We assessed trends using average annual percentage changes (AAPCs) and measured cross-country inequalities using the slope index of inequality and concentration index.

Results: The global age-standardised DALY rates of ADRDs per 100 000 population slightly increased from 1331.59 (95% confidence interval (CI) = 881.57, 1781.61) in 1990 to 1347.24 (95% CI = 906.36, 1788.12) in 2021, with an AAPC of 0.04% (95% CI = 0.02, 0.05). The global age-standardised QCI-v of ADRDs increased from 51.56 (95% CI = 45.87, 57.26) to 54.27 (95% CI = 48.68, 59.86), with an AAPC of 0.16% (95% CI = 0.12, 0.21). Regions with a low-middle or low sociodemographic index (SDI), as well as the African Region and the South-East Asia Region, experienced an increasing burden, but a decreasing care quality. In 2021, high-middle SDI regions and the Western Pacific Region had the highest burden, while care quality was notably low in low SDI region. The European Region showed the greatest inequality in terms of burden, while the Eastern Mediterranean showed marked disparities in care quality.

Conclusions: The disease burden and care quality of ADRDs both increased from 1990 to 2021, accompanied by significant disparities between countries. Regions with low-middle or low SDI, particularly the African and South-East Asia Regions, faced rising burdens and declining care quality.