Large Discrepancies in Dementia Mortality Reported in Vital Statistics: The Need for Improved Data to Inform Policy.

Purpose: There is limited understanding of the intercountry comparability of dementia mortality data. This study compares reported dementia mortality in national vital statistics between countries and over time. In countries with low dementia reporting, this study identifies other causes to which dementia may be misclassified.

Methods: Using the World Health Organization (WHO) Mortality Database, we calculated the ratio of reported to expected (Global Burden of Disease estimated) age-standardized dementia death rates in 90 countries from 2000 to 2019. Other causes to which dementia may be misclassified were identified as having relatively high cause fractions compared with other countries.

Patients: No patients were involved.

Results: There is a large intercountry variation in reported dementia mortality rates. The ratio of reported to expected dementia mortality exceeded 100% in high-income countries but was below 50% in other super regions. In countries with low reported dementia mortality, cardiovascular diseases, ill-defined causes, and pneumonia have relatively high cause fractions and may be misclassified from dementia.

Discussion: Large discrepancies in dementia mortality reporting between countries, including often implausibly low reported mortality, makes comparison extremely difficult. Improved guidance for and training of certifiers and the use of multiple cause-of-death data can help strengthen the policy utility of dementia mortality data.