Regional inequities in myocardial infarction burden in Brazil’s public healthcare system

BACKGROUND: Myocardial infarction (MI) remains a leading cause of morbidity and mortality, with an uneven burden across Brazil. We evaluated trends in emergency MI hospitalizations, in-hospital mortality, and standardized costs within Brazil's Unified Health System (SUS) from 2008 to 2023, with emphasis on regional disparities and the COVID-19 period. METHODS: We performed a retrospective observational analysis using SUS Hospital Information System (SIH/SUS) data. Age- and sex-standardized rates were calculated for emergency MI hospitalizations and in-hospital mortality; standardized costs were expressed as BRL per hospital day and adjusted for inflation and regional purchasing power. Five-year interval means, cumulative changes, and Z-tests with 95% confidence intervals (95% CI) were computed. To assess associations between health-system supply factors (primary care capillarity, inpatient capacity, and workforce) and MI outcomes, we estimated region-year two-way fixed-effects panel regressions using lagged supply indices derived from CNES/TABNET. Corresponding linear two-way fixed-effects trend panels are presented to visualize the model-implied within-region linear associations. RESULTS: Emergency MI hospitalization rates increased by 145.91% nationally from 2008 to 2023, with the greatest growth in the Central-West (+ 240.88%). The South and Southeast consistently recorded the highest hospitalization and mortality rates, while the North and Northeast - despite lower baseline rates - showed the steepest proportional growth, raising important equity concerns. In-hospital mortality increased by 166.67% nationally, with marked worsening during the COVID-19 period (2020-2022). In contrast, standardized cost per hospital day declined nationally by 7.38% across five-year means (768.69 to 663.98 BRL/day; p < 0.001), remaining highest in the South (1102.69 BRL/day in 2018-2022) and declining most in the North (684.38 to 465.70 BRL/day; p < 0.001). In supply-side panel analyses, inpatient-capacity expansion was most consistently associated with lower per-day reimbursement intensity and lower MI hospitalization rates within regions over time; supply indices showed limited association with in-hospital mortality. CONCLUSION: MI burden in Brazil's SUS rose substantially from 2008 to 2023, with persistent regional inequities and worsened outcomes during the pandemic. Inpatient-capacity expansion was the supply domain most consistently linked to MI utilization and cost variation, though all associations are ecological rather than causal. Standardized per-day inpatient costs did not rise commensurately with the growing clinical burden, suggesting that reimbursement/resource intensity per hospital day did not expand in step with demand. These findings support region-specific efforts to strengthen timely, evidence-based acute MI care - particularly in the North and Northeast, where demand is rising fastest against a backdrop of structural resource constraints.