Infective endocarditis (IE) is most commonly caused by viridans streptococci.¹ Risk factors include valvular heart disease, prosthetic valves, grafts or intracardiac devices, congenital heart disease, and prior IE.^2,3

Mortality estimates vary due to differences in diagnostic criteria. Over the past two decades, population-based studies in high-income countries have reported 30-day (in-hospital) mortality of 11%-25%.³ In the United States, morbidity and mortality occur in 16%-30% of cases involving prosthetic-valve and in 25%-35% of cases involving native valves treated in hospital settings.⁴ Globally, up to 77% of IE cases are estimated to occur in developing countries, although this figure may be affected by reporting practices and access to care. In Brazil, rheumatic heart disease remains a predominant valvular substrate; however, the disease's declining prevalence in developing nations has limited country-specific analyses.⁵

Clinically, IE may present acutely, evolve subacutely (often on pre-existing valvular lesions), or follow an indolent course over weeks to months.^6,7 Cardiac conditions that produce turbulent flow (eg, mitral valve prolapse, hypertrophic cardiomyopathy, and cyanotic congenital heart disease) increase the risk of IE by promoting mechanical injury that leads to subsequent valvular degeneration and calcification.^8,9

Because of its global and national significance, this study outlines the epidemiological profile of IE mortality in Brazil over the past 27 years. It characterizes the distribution of IE and its associated risk factors in order to inform public policies and guide future strategies.

Using SIM data from 1996 to 2023, chi-square tests of independence showed significant differences across years (p < 0.05). As detailed in Table 1 and Central Illustration, the annual count peaked in 2023 at 2,279 deaths (5.68% of the total) and was lowest in 1996 at 689 deaths (1.72%). Deaths were classified by region and ICD-10 category — I33 and I38. A total of 40,157 deaths were recorded (chi-square = 1,701.43), which represents a 230.77% increase over the study period.

Based on SIM data from 1996 2023, chi-square tests of independence showed statistically significant differences in region and sex (p < 0.001). The Southeast region had the highest number of deaths, with 21,429 deaths (53.36%; chi-square = 15,236.00), followed by the Northeast (7,432; 18.51%), the South (6,771; 16.86%), the Central-West (2,939; 7.32%), and the North (1,586; 3.95%) (Table 2).

By sex, males predominated (chi-square = 999.32; p < 0.001), comprising 22,315 deaths (55.57%), while females accounted for 17,835 (44.41%) deaths. Sex was unspecified in seven records (0.02%) (Table 3).

This study reveals a consistent rise in deaths due to acute and subacute endocarditis in Brazil between 1996 and 2023, amounting to 40,157 fatalities. There were 698 deaths in 1996, rising to 2,279 in 2023 — a 230.77% increase. This progressive increase may be due to population aging, the increased use of implantable cardiac devices, and the spread of resistant pathogens.¹⁰ Improvements in reporting and diagnostic sensitivity, particularly with echocardiography, may also contribute.¹¹

Although this dataset could not identify individual cases of co-infection with COVID-19, the pandemic years (2020-2022) showed a statistically significant increase in IE mortality. Causality cannot be established; however, the available evidence suggests that the pandemic may have indirectly influenced IE outcomes. International reports describe uncommon cases of coinfection with both COVID-19 and IE, predominantly in middle-aged men, with frequent aortic valve involvement and complications such as pulmonary edema and embolic events.¹² Respiratory manifestations of COVID-19 can mask or delay IE diagnosis, potentially worsening outcomes. Additional factors, such as diagnostic delays, health system strain, and secondary infections (particularly those caused by Staphylococcus aureus), may also have contributed.¹³ These observations underscore the need for ongoing surveillance, timely reporting, and high clinical suspicion for IE during overlapping infectious outbreaks to mitigate adverse outcomes in high-risk groups.

Geographically, the Southeast accounted for the largest proportion of deaths (53.36%; 21,429), followed by the Northeast (18.51%; 7,432), the South (16.86%; 6,771), the Central-West (7.32%; 2,939), and the North (3.95%; 1,586). This concentration likely reflects population size and greater diagnostic and reporting capacity. Brazil has 598,573 physicians, 182,852 of whom (30.5%) are in the Southeast.¹⁴ Of the 20,324 cardiologists nationwide, 10,770 practice in the Southeast — more than half of the national total.¹⁵ Greater diagnostic availability may therefore increase case ascertainment in the region rather than indicating an intrinsically higher mortality risk.

A male predominance was observed (55.57% vs. 44.41% among females). While secondary databases are subject to underreporting and coding variability, this pattern aligns with international and regional data. Large cohorts have documented higher IE incidence among men, suggesting biological and behavioral contributors. For example, Østergaard et al. (2019) reported a significantly higher incidence among high-risk men in Denmark.¹⁶ Likewise, a Latin American systematic review found a male predominance across clinical and microbiological series with cross-country variability.¹⁷

Proposed explanations include behavioral risk factors (eg, higher prevalence of injection drug use, alcohol consumption, and health care-associated exposures in men) as well as sex-related differences in immune and cardiovascular responses. However, these differences should be interpreted cautiously, as mortality proportions from administrative data may also reflect biases in access to care and diagnosis.¹⁶

According to Lima et al.,¹ IE is a life-threatening condition with a challenging diagnosis that demands precise investigative approaches to optimize clinical outcomes and mitigate disease burden.

This study demonstrates a substantial and progressive increase in IE-related mortality in Brazil from 1996 to 2023, with a total of 40,157 deaths — a 230.77% increase over the study period. The Southeast region had the highest number of deaths, which is consistent with its larger population and greater concentration of health professionals, including cardiologists. A male predominance (55.57%) was observed, suggesting behavioral and biological contributors to risk.

Chi-square tests of independence revealed significant differences by year (p < 0.05), region, and sex (p < 0.001), indicating a nonrandom distribution of deaths and supporting the robustness of these findings. These results underscore the need for continued epidemiological surveillance and improved case reporting, particularly in high-risk regions and populations.