Cardiovascular epidemiological transition among young Brazilians: a time-series analysis, Brazil, 2008-2024

Objective: To comparatively analyze temporal trends in acute myocardial infarction hospitalizations versus heart failure hospitalizations among young adults (<45 years old) in Brazil between 2008 and 2024. Methods: A time-series analysis was conducted using aggregated secondary data from the Brazilian Unified Health System Hospital Information System for individuals under 45 years of age treated in Brazil. Hospitalization rates per 100,000 inhabitants were calculated. Poisson regression was used to estimate the Relative Incidence Rate, and segmented regression (using the R 4.3.0 ‘segmented’ package) was employed to identify inflection points in the temporal trends. Results: A total of 146,230 acute myocardial infarction and 314,098 heart failure hospitalizations were analyzed. The acute myocardial infarction hospitalization rate rose from 4.06 to 9.29 per 100,000 inhabitants (Relative Incidence Rate: 1.06; 95%CI 1.05;1.07; p-value<0.001), with inflection points observed in 2009 and 2020. Heart failure hospitalization rates declined from 17.88 to 11.31 per 100,000 inhabitants. The ratio between the rates evolved from 0.23 to 0.82. Mean in-hospital mortality due to infarction was 4.8%. Infarction hospitalization rates were 142.5 per 100,000 for men and 61.5 per 100,000 for women. Conclusion: The increase in acute myocardial infarction hospitalizations and their progressive convergence with heart failure rates indicate a shift in the cardiovascular profile of the young population served by the Brazilian Unified Health System, with infarction playing an increasingly significant role as a cause of hospitalization in this age group throughout the period analyzed.