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An analysis of a global data set shows the burden of atrial fibrillation (AF) and atrial flutter (AFL) climbed sharply between 1990 and 2019, with women accounting for much of the increase, and factors such as obesity and alcohol use replacing smoking as key drivers of the disease, according to a study published Wednesday in the Journal of the American Heart Association.

Investigators used the Global Burden of Disease data set, along with information from the World Health Organization and the World Bank to gain a comprehensive look at AF and AFL, which cause strokes and heart failure and are associated with rising health care costs, morbidity, and mortality. The underlying data were collected by more than 9000 researchars in 160 countries, and show the following:

  • The absolute number of AF/AFL cases more than doubled from 1990 to 2019, from 28,273,978, to 56,671,814.
  • The increase in prevalence has been greatest in middle-income countries, with an increase of 146.6% in lower-middle income countries and 145.2% in upper middle income countries.
  • In low-income countries, the prevalence rose 120.7%.
  • In high-income countries, the prevalence rose by 67.8%; these countries had the highest absolute prevalence until 2014, investigators reported, but then saw a leveling-off, and cases rose more quickly in middle-income countries.
  • High-income countries still have the highest number of cases across the population, with 1738 per 100,000 population, more than double the 844 per 100,000 in upper middle-income countries.

Deaths from these conditions have climbed 202.3% in upper middle-income countries and by 227.4% in lower middle-income countries; while in low-income countries, deaths have risen 162.3%. Absolute numbers of deaths are still highest in upper income countries and they rose 131.3%. The numbers in high income countries are driven by the fact that so many more women have AF/AFL, according to the study authors.

Why the increase in cases? The most obvious reason is the overall growth in population, but other reasons are complex, the authors say. “National income groups are defined by economic factors, but there are further characteristics that differ between income groups,” they wrote, “Some are related to income, such as socioeconomic status and health care infrastructure, others are independent, such as geographic and thus also racial differences.”

More cases are occurring among younger individuals in low- and middle-income countries, and among more older persons in high-income countries. Even greater age disparities can be seen between income groups in deaths, they write.

Some risk factors, such as age, are not modifiable, but others are—and those are shifting.

“Risk factors such as BMI, alcohol consumption, and insufficient physical activity show a clear trend toward higher rates in high-income countries,” the authors found. “Raised fasting blood glucose and current tobacco use have the highest rates in middle-income countries,” and elevated blood pressure is now easing as income rises, “which is a new trend.”

The investigators note there is considerable underrepresentation of low- and middle-income countries in research on AF/AFL, and it not well-known how much research from high-income countries can be generalized for these populations.