Sex Differences in Characteristics of Patients with Infective Endocarditis: A Multicenter Study

Infective Endocarditis Among Women Who Inject Drugs

Importance

In the US and Canada, women comprise approximately one-third of people who inject drugs (PWID); however, clinical characteristics and outcomes of injection drug use complications in women are poorly described.

Objective

To identify clinical characteristics and outcomes of infective endocarditis (IE) among women who inject drugs (WWID).

Design, Setting, and Participants

This is a retrospective cohort study of PWID with definite IE (per 2023 Duke-International Society for Cardiovascular Infectious Diseases criteria) admitted from April 5, 2007, to March 15, 2018, at 5 tertiary-care hospitals in London, Ontario, and Regina, Saskatchewan, Canada. Data were analyzed from June 1, 2023, to August 2, 2024. Descriptive analyses were conducted for baseline characteristics at index hospitalization and stratified by sex.

Main Outcomes and Measures

The primary outcome was the difference in 5-year survival between female and male PWID with IE. The secondary outcome was 1-year survival. Multivariable time-dependent Cox proportional hazards regression analyses were conducted for variables of clinical importance to evaluate 5-year mortality.

Results

Of 430 PWID with IE, 220 (51.2%) were women; of 332 non-PWID with IE, 101 (30.4%) were women. WWID with IE were younger than men (median [IQR] age, 31.5 [27.0-38.5] vs 38.5 [31.0-49.0] years), and 11 of 220 (5.0%) were pregnant at index hospitalization, although only 12 of 220 (5.5%) had contraceptive use documented. Women had a larger proportion of right-sided IE than men (158 of 220 women [71.8%] vs 113 of 210 men [53.8%]). WWID living in urban areas had higher mortality than WWID in rural areas (adjusted hazard ratio [aHR], 2.70; 95% CI, 1.15-6.34; P = .02). Overall mortality was lower among PWID referred for substance use disorder counseling in centers with inpatient services compared with centers with only outpatient referrals (aHR, 0.29; 95% CI, 0.17-0.51; P < .001). Overall mortality was lower with right-sided heart disease for both women (aHR, 0.44; 95% CI, 0.27-0.71; P < .001) and men (aHR, 0.22; 95% CI, 0.10-0.50; P < .001) and was higher with congestive heart failure for both women (aHR, 2.32; 95% CI, 1.29-4.18; P = .005) and men (aHR, 1.73; 95% CI, 1.07-2.79; P = .02).

Conclusions and Relevance

In this cohort of PWID with IE, women were overrepresented. Reasons for women's disproportionately high IE incidence need further study. Inpatient substance use disorder services, contraception counseling, and enhanced social support for WWID living in urban areas need to be prioritized.

Sex differences and outcomes in surgical infective endocarditis

BACKGROUND

Cardiac surgery for infective endocarditis (IE) is associated with significant hospital mortality, and female sex may be associated with worse outcomes. However, the impact of sex on the presenting characteristics, management, and outcomes of patients operated on for acute infective endocarditis (IE) has not been adequately studied.

OBJECTIVES

The goal of our study was to analyse differences in management and outcome of IE between women and men who undergo surgery.

METHODS

Clinical data of 717 patients undergoing cardiac surgery for IE between December 2005 and December 2019 were prospectively collected. Sex-related postoperative outcomes including in-hospital mortality were recorded. Univariable and multivariable analyses were performed to identify potential sex-related determinant of in-hospital mortality.

RESULTS

In all, 532 male patients (74.2%) and 185 female patients (25.8%) underwent surgery for IE. At baseline, women had more frequent mitral regurgitation with 63 patients (34.1%) than men with 135 patients (25.4%) (P = 0.002). Female sex was associated with higher in-hospital mortality (23.2% versus 17.3%, P = 0.049). However, multivariable analysis revealed age (P < 0.01), antibiotics < 7 days before surgery (P = 0.01) and staphylococcal IE (P < 0.01) but not female sex (P = 0.99) as independent determinants of hospital mortality.

CONCLUSIONS

In this study of patients operated-on for IE, female sex was associated with more severe manifestations of IE and significantly higher in-hospital mortality. However, after multivariable analysis, initial presentation, but not sex, seemed to determine clinical outcomes.

Endocarditis, drug use and biological sex: A statewide analysis comparing sex differences in drug use-associated infective endocarditis with other drug-related harms

OBJECTIVES

Hospitalizations for drug use-associated infective endocarditis (DUA-IE) have risen sharply across the United States over the past decade. The sex composition of DUA-IE remains less clear, and studies have indicated a possible shift to more females. We aimed to compare more recent statewide hospitalization rates for DUA-IE in females versus males and contextualize them among other drug-related harms in North Carolina (NC).

METHODS

This study was a retrospective analysis using public health datasets of all NC hospital discharges for infective endocarditis from 2016 to 2020. Drug use-related hospitalizations were identified using ICD-10-CM codes. Discharge rates by year and sex for DUA-IE and non-DUA-IE were calculated and compared to fatal overdoses and acute hepatitis C (HCV). Temporal, demographic, and pregnancy trends were also assessed.

RESULTS

Hospitalizations rates for DUA-IE were 9.7 per 100,000 over the five-year period, and 1.2 times higher among females than males. Females composed 57% of DUA-IE hospitalizations over the period. Conversely, fatal overdose, acute HCV, and non-DUA-IE hospitalization rates were higher among males. Age, county of residence, and pregnancy status did not explain the higher DUA-IE among females.

CONCLUSION

Females now comprise the majority of DUA-IE hospitalizations in NC, unlike other drug-related harms. No clear demographic or geographic associations were found, and further research is needed to explain this phenomenon. Preventing invasive infections among females who inject drugs should be prioritized.

Sex Differences in Infective Endocarditis: A Systematic Review

Despite the advancement in medicine, there is still a lack of understanding of the sex disparities in disease onset, progression, treatment, and outcome. In some life-threatening acute conditions, despite most patients with these illnesses being males, females have a significantly higher chance of mortality. This can be due to the differences in disease progression or healthcare disparities in managing the illness between the sexes. Treatment of illnesses tends to be more conservative for women without an explanation, but this disparity is due to the healthcare provider. Infective endocarditis (IE) is an acute life-threatening condition where bacteria latch onto and seed damaged endocardium, with some preliminary information reporting differences between the sexes. This paper aims to evaluate the sex disparities in the incidence, age, comorbidities, etiology, risk factors, manifestations, treatment, and outcomes of IE. From 2003-2023, 21584 articles were found that focused on the sex differences in IE and, through PRISMA guidelines, were narrowed down to 34 publications. There are significant differences between the sexes in IE, such as a significantly higher incidence of IE in males, who also tend to be older and have their native aortic valves involved, compared to younger females who have their mitral valve involved. Comorbidities also vary between the sexes; females tend to have atrial fibrillation, chronic kidney disease, psychiatric disorders, and taking immunosuppressants compared to males who suffer from chronic liver disease, underlying valve disease, and peripheral artery disease, contributing to the ease of developing IE. While the most common microorganism leading to IE is Staphylococcus aureus, females were more likely to have culture-negative IE, and men were more likely to be infected with Streptococcus viridans. Major manifestations in IE are fever and vegetation along the closure of the valves in the heart, where females were more likely to have vegetation on the mitral and aortic valves. At the same time, males were more likely to have it on the tricuspid valve. On par with sex disparities in health, females usually took longer to seek medical help than males despite the advancement of symptoms and deterioration. Females were also treated conservatively through antibiotic management, whereas males were more likely to advance to surgical treatment, leading to a longer hospital stay. While there was no true difference in the in-hospital mortality rate, the 30-day and 1-year mortality were significantly increased in females. These differences provide a range of starting points for various research to further educate physicians on sex disparities, such as why males have a higher incidence of infective endocarditis and determining whether it's hormones and basic metabolites, possibly limiting those who develop the infection. Another important point is treating females with IE; the antibiotic doses are standard, but whether they advance to surgical treatment is mostly up to the provider. Some providers deny surgical treatment despite all indications, but it could also be females denying surgery as they tend to leave against medical advice. This review is crucial in developing the next steps to sex disparity in IE, which may lead to better outcomes for males and females.