Explaining sex differences in risk of bloodstream infections using mediation analysis in the population-based HUNT study in Norway

Molecular epidemiology of Escherichia coli in bloodstream infections from a general hospital in Ningxia, China, 2022-2023

OBJECTIVE

To analyse the antibiotic resistance, resistance genes and clonal relationship of Escherichia coli in bloodstream infections in Ningxia from 2022 to 2023.

METHODS

We retrospectively analyzed the antibiotic susceptibilities of 257 isolates. PCR was used to detect blaTEM, blaSHV, blaCTX-M, qnrS, qnrA, qnrB, oqxA, qepA, gyrA, gyrB, parC, and parE, and the clonal relationship through multilocus sequence typing (MLST).

RESULTS

One hundred and twenty-nine of 257 patients were male (50.2%). The 257 E. coli isolates were mainly obtained from the Emergency, Hepatobiliary Surgery, and Haematology Departments, accounting for 56.6%, 7.3%, and 6.2%, respectively. There is no significant difference in sex and genes between the two groups over and under 60 years old (P > 0.05), but there is a significant difference in ST between them(P<0.05). The antimicrobial susceptibility testing showed that the 257 isolates had the highest rates of resistance to ampicillin (82.8%), followed by cefazolin (71.6%), and all isolates were susceptible to tigecycline. Based on the antibiotic susceptibility results for ceftriaxone, we tested 126 isolates of E. coli for extended-spectrum beta-lactamase (ESBL) resistance genes. As a result, blaCTX-M was detected in 76 isolates (60.32%), blaSHV in 26 isolates (20.63%), and blaTEM in 38 isolates (30.16%). Based on the ciprofloxacin and levofloxacin antibiotic susceptibility results, we tested for quinolone resistance genes in 148 isolates, revealing 66 isolates of aac(6')-Ib-cr (44.60%), 3 isolates of oqxA (2.02%), 32 isolates of qnrS (21.62%), and 2 isolates of qepA (1.35%). We did not detect qnrA or qnrB. The detection rates of gyrA, gyrB, parC, and parE were 98%, 42.6%, 91.2%, and 87.8%, respectively and the main amino acid mutations were Ser83 to Leu, Asp87 to Asn(75.2%), Leu417 to Ser, Ser418 to Leu (6.3%), Ser80 to Ile (65.2%), and Ser458 to Ala (21.5%), respectively. MLST revealed that the most common sequence types (STs) were ST69 (12.5%), ST131 (8.2%), and ST1193 (7.8%).

CONCLUSION

In our hospital, E. coli was resistant to most commonly used antibiotics, and cefoperazone/sulbactam, cefotetan, amikacin, and tigecycline were empirically selected for the treatment of bloodstream infections. The predominant ESBL genotype in our hospital was blaCTX-M and the major quinolone resistance gene was aac(6')-Ib-cr. Clonal relationship analysis revealed genetic diversity among the isolates.

Tossing the coin of extended-spectrum β-lactamase: prevalence of extended-spectrum β-lactamase-producing Klebsiella pneumoniae isolated from patients with sepsis

Background. Klebsiella pneumoniae is part of the ESKAPE (Enterococcus faecium, Staphylococcus aureus, K. pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa and Enterobacter spp.) group of multidrug-resistant (MDR) pathogens. K. pneumoniae is the leading cause of antimicrobial resistance-associated mortality and the second leading cause of nosocomial bloodstream infections (BSIs), globally and in sub-Saharan Africa. Therefore, it was aimed to determine the antibiotic resistance patterns of K. pneumoniae isolated from blood cultures of patients with features of sepsis at Mulago National Referral Hospital, Uganda. Methods. The cross-sectional study on patients with features of sepsis utilized K. pneumoniae (n=30) isolated from positive blood culture specimens. The antibiotic resistance profile was determined by the Clinical and Laboratory Standards Institute's Kirby-Bauer disc diffusion method, which was used to classify the isolates as susceptible, intermediate and resistant. K. pneumoniae isolates that were resistant to third-generation cephalosporins were subjected to extended-spectrum β-lactamase (ESBL) screening and confirmation using the double-disc synergy test using cefotaxime, ceftazidime, ceftriaxone, cefotaxime-clavulanic acid and ceftazidime-clavulanic acid. The results were analysed for frequencies. Results. K. pneumoniae isolates showed emerging resistance to imipenem at 13% (4 out of 30) followed by amikacin at 17% (5 out of 30). There was intermediate resistance to gentamycin at 60% (18 out of 30). However, K. pneumoniae showed the highest resistance to piperacillin at 100% (30 out of 30) followed by sulphamethoxazole-trimethoprim and cefepime, both showing a percentage of 97% (29 out of 30). Up to 16 out of 30 (53.3%) of K. pneumoniae were positive for ESBL production, whilst 14 out of 30 (46.7%) were negative. Conclusion. There was a high prevalence of antibiotic-resistant ESBL-producing K. pneumoniae isolates from BSI of patients with features of sepsis in Uganda's Mulago National Referral Hospital.

Trends in sepsis-associated cardiovascular disease mortality in the United States, 1999 to 2022

Purpose

Cardiovascular disease (CVD) is the leading cause of death in the United States, and sepsis significantly contributes to hospitalization and mortality. This study aims to assess the trends of sepsis-associated CVD mortality rates and variations in mortality based on demographics and regions in the US.

Methods

The Centers for Disease Control and Prevention Wide-ranging Online Data for Epidemiologic Research (CDC WONDER) database was used to identify CVD and sepsis-related deaths from 1999 to 2022. Data on gender, race and ethnicity, age groups, region, and state classification were statistically analyzed to obtain crude and age-adjusted mortality rates (AAMR). The Joinpoint Regression Program was used to determine trends in mortality within the study period.

Results

During the study period, there were a total of 1,842,641 deaths with both CVD and sepsis listed as a cause of death. Sepsis-associated CVD mortality decreased between 1999 and 2013, from AAMR of 65.7 in 1999 to 58.8 in 2013 (APC -1.06*%, 95% CI: -2.12% to -0.26%), then rose to 74.3 in 2022 (APC 3.23*%, 95% CI: 2.18%-5.40%). Throughout the study period, mortality rates were highest in men, NH Black adults, and elderly adults (65+ years old). The Northeast region, which had the highest mortality rate in the initial part of the study period, was the only region to see a decline in mortality, while the Northwest, Midwest, and Southern regions experienced significant increases in mortality rates.

Conclusion

Sepsis-associated CVD mortality has increased in the US over the past decade, and both this general trend and the demographic disparities have worsened since the onset of the COVID-19 pandemic.

Sex-Disaggregated Analysis of Central Venous Catheter-Related Bloodstream Infections in Patients with Cancer

INTRODUCTION

Men are generally more susceptible to bacterial infections than women. Central venous catheters (CVCs), often used to administer systemic treatment in patients with cancer, are an important source of infection. However, little is known about sex-specific differences of CVC-related bloodstream infections (CRBSIs) in patients with cancer. This study aimed to compare CRBSIs in men versus women in a large cohort of patients with cancer.

METHODS

Data were derived from the SECRECY registry including nonselected patients with centrally inserted non-tunneled internal jugular or subclavian vein CVCs in 10 hematology and oncology sites in Germany. Only CRBSIs classified as definite CRBSI (dCRBSI) or probable CRBSI were included, and the combination of both was summarized as dpCRBSI. CVCs were matched 1:1 for underlying disease, anatomic site of CVC insertion, type of CVC dressing, antimicrobial coated CVC, complicated CVC insertion, and CVC in situ time by propensity score matching (PSM). Endpoints were CRBSI rates and incidences in CVCs inserted in men versus women.

RESULTS

A total of 5,075 CVCs registered from March 2013 to March 2024 were included in the analysis, of which 3,024 comprise the PSM cohort. A total of 1,512 (50.0%) CVCs were inserted in men. Underlying diseases mainly were hematological malignancies (96.4%). While there was no statistically significant difference between men and women in the dCRBSI rate (5.4% vs. 4.1%; p = 0.12) and the dCRBSI incidence (3.8 vs. 2.9/1,000 CVC days; p = 0.11), the rate of dpCRBSI (9.9% vs. 6.7%; p = 0.002) and the dpCRBSI incidence (7.0 vs. 4.7/1,000 CVC days; p = 0.002) were significantly higher in men versus women. The proportion of coagulase-negative staphylococci as causative agent of both dCRBSI and dpCRBSI was higher in men than in women (58.8% vs. 41.2%; p = 0.07 and 61.5% vs. 38.5%; p = 0.002, respectively). A multivariable regression revealed neutropenia as an independent risk factor for dCRBSI and male sex as risk factor for dCRBSI and dpCRBSI.

CONCLUSION

In patients with hematological malignancies, men have a higher risk of CRBSI than women. This finding may be attributed to the high number of jugular vein-inserted CVCs, which in men may be associated with higher rates of skin colonization than in women. Special preventive measures such as earlier removal of CVCs in men may be studied in future.

INTRODUCTION

Men are generally more susceptible to bacterial infections than women. Central venous catheters (CVCs), often used to administer systemic treatment in patients with cancer, are an important source of infection. However, little is known about sex-specific differences of CVC-related bloodstream infections (CRBSIs) in patients with cancer. This study aimed to compare CRBSIs in men versus women in a large cohort of patients with cancer.

METHODS

Data were derived from the SECRECY registry including nonselected patients with centrally inserted non-tunneled internal jugular or subclavian vein CVCs in 10 hematology and oncology sites in Germany. Only CRBSIs classified as definite CRBSI (dCRBSI) or probable CRBSI were included, and the combination of both was summarized as dpCRBSI. CVCs were matched 1:1 for underlying disease, anatomic site of CVC insertion, type of CVC dressing, antimicrobial coated CVC, complicated CVC insertion, and CVC in situ time by propensity score matching (PSM). Endpoints were CRBSI rates and incidences in CVCs inserted in men versus women.

RESULTS

A total of 5,075 CVCs registered from March 2013 to March 2024 were included in the analysis, of which 3,024 comprise the PSM cohort. A total of 1,512 (50.0%) CVCs were inserted in men. Underlying diseases mainly were hematological malignancies (96.4%). While there was no statistically significant difference between men and women in the dCRBSI rate (5.4% vs. 4.1%; p = 0.12) and the dCRBSI incidence (3.8 vs. 2.9/1,000 CVC days; p = 0.11), the rate of dpCRBSI (9.9% vs. 6.7%; p = 0.002) and the dpCRBSI incidence (7.0 vs. 4.7/1,000 CVC days; p = 0.002) were significantly higher in men versus women. The proportion of coagulase-negative staphylococci as causative agent of both dCRBSI and dpCRBSI was higher in men than in women (58.8% vs. 41.2%; p = 0.07 and 61.5% vs. 38.5%; p = 0.002, respectively). A multivariable regression revealed neutropenia as an independent risk factor for dCRBSI and male sex as risk factor for dCRBSI and dpCRBSI.

CONCLUSION

In patients with hematological malignancies, men have a higher risk of CRBSI than women. This finding may be attributed to the high number of jugular vein-inserted CVCs, which in men may be associated with higher rates of skin colonization than in women. Special preventive measures such as earlier removal of CVCs in men may be studied in future.

Impact of ESKAPE Pathogens on Bacteremia: A Three-Year Surveillance Study at a Major Hospital in Southern Italy

BACKGROUND/OBJECTIVES

ESKAPE pathogens (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter spp.) pose a serious public health threat as they are resistant to multiple antimicrobial agents. Bloodstream infections (BSIs) caused by ESKAPE bacteria have high mortality rates due to the limited availability of effective antimicrobials. This study aimed to evaluate the prevalence and susceptibility of ESKAPE pathogens causing BSIs over three years in a large tertiary hospital in Salerno.

METHODS

Conducted at the Clinical Microbiology Laboratory of San Giovanni di Dio e ''Ruggi D'Aragona'' Hospital from January 2020 to December 2022, blood culture samples from different departments were incubated in the BD BACTEC™ system for 5 days. Species identification was performed using MALDI-TOF MS, and antimicrobial resistance patterns were determined by the VITEK2 system.

RESULTS

Out of 3197 species isolated from positive blood cultures, 38.7% were ESKAPE bacteria. Of these, 59.9% were found in blood culture samples taken from men, and the most affected age group was those aged >60 years. (70.6%). Staphylococcus aureus was the main BSI pathogen (26.3%), followed by Klebsiella pneumoniae (15.8%). Significant resistance rates were found, including 35% of Staphylococcus aureus being resistant to oxacillin and over 90% of Acinetobacter baumannii being resistant to carbapenems.

CONCLUSIONS

These results highlight the urgent need for antimicrobial stewardship programs to prevent incurable infections.

Sex-related immunity: could Toll-like receptors be the answer in acute inflammatory response?

An increasing number of studies have highlighted the existence of a sex-specific immune response, wherein men experience a worse prognosis in cases of acute inflammatory diseases. Initially, this sex-dependent inflammatory response was attributed to the influence of sex hormones. However, a growing body of evidence has shifted the focus toward the influence of chromosomes rather than sex hormones in shaping these inflammatory sex disparities. Notably, certain pattern recognition receptors, such as Toll-like receptors (TLRs), and their associated immune pathways have been implicated in driving the sex-specific immune response. These receptors are encoded by genes located on the X chromosome. TLRs are pivotal components of the innate immune system, playing crucial roles in responding to infectious diseases, including bacterial and viral pathogens, as well as trauma-related conditions. Importantly, the TLR-mediated inflammatory responses, as indicated by the production of specific proteins and cytokines, exhibit discernible sex-dependent patterns. In this review, we delve into the subject of sex bias in TLR activation and explore its clinical implications relatively to both the X chromosome and the hormonal environment. The overarching objective is to enhance our understanding of the fundamental mechanisms underlying these sex differences.

The Assessment of Infection Risk in Patients with Vitiligo Undergoing Dialysis for End-Stage Renal Disease: A Retrospective Cohort Study

Vitiligo is an autoimmune condition that causes patchy skin depigmentation. Although the mechanism by which vitiligo induces immunocompromise is unclear, other related autoimmune diseases are known to predispose those affected to infection. Individuals with vitiligo exhibit epidermal barrier disruption, which could potentially increase their susceptibility to systemic infections; patients with renal disease also show a predisposition to infection. Nevertheless, there is little research addressing the risk of infection in dialysis patients with vitiligo in comparison to those without it. A retrospective analysis was performed on patients with end-stage renal disease (ESRD) in the United States Renal Data System who started dialysis between 2004 and 2019 to determine if ESRD patients with vitiligo are at an increased risk of bacteremia, cellulitis, conjunctivitis, herpes zoster, or septicemia. Multivariable logistic regression modeling indicated that female sex, black compared to white race, Hispanic ethnicity, hepatitis C infection, and tobacco use were associated with an enhanced risk of vitiligo, whereas increasing age and catheter, versus arteriovenous fistula, and access type were associated with a decreased risk. After controlling for demographics and clinical covariates, vitiligo was found to be significantly associated with an increased risk of bacteremia, cellulitis, and herpes zoster but not with conjunctivitis and septicemia.

Trends in Antibiotic Resistance Patterns and Burden of Escherichia Coli Infections in Young Children: A Retrospective Cross-Sectional Study in Shenzhen, China from 2014-2018

Purpose

The emergence of multi-drug resistant ESBL-producing E. coli poses a global health problem. In this study, we aimed to investigate the prevalence of E. coli infections and their antibiotic susceptibility profiles in paediatric clinical cases in Shenzhen, China from Jan 1, 2014, to Jan 30, 2019, while also determining temporal trends, identifying ESBL-producing strains, and recommending potential empirical antibiotic therapy options.

Methods

We isolated a total of 4148 E. coli from different specimens from a single paediatric healthcare centre. Additionally, we obtained relevant demographic data from the hospital's electronic health records. Subsequently, we performed antimicrobial susceptibility testing for 8 classes of antibiotics and assessed ESBL production.

Results

Out of the 4148 isolates, 2645 were from males. The highest burden of E. coli was observed in the age group of 0-1 years, which gradually declined over the five-year study period. Antimicrobial susceptibility results indicated that 82% of E. coli isolates were highly resistant to ampicillin, followed by 52.36% resistant to cefazolin and 47.46% resistant to trimethoprim/sulfamethoxazole. Notably, a high prevalence of ESBL production (49.54%) was observed among the E. coli isolates, with 60% of them displaying a multi-drug resistance phenotype. However, it is worth mentioning that a majority of the isolates remained susceptible to ertapenem and imipenem. Our findings also highlighted a decrease in E. coli infections in Shenzhen, primarily among hospitalized patients in the 0-1 year age group. However, this decline was accompanied by a considerably high rate of ESBL production and increasing resistance to multiple antibiotics.

Conclusion

Our study underscores the urgent need for effective strategies to combat multi-drug resistant ESBL-producing E. coli Infections.

Risk Factor for Superimposed Nosocomial Bloodstream Infections in Hospitalized Patients with COVID-19

Introduction

Corticosteroids are a component of the standard therapy for patients with coronavirus disease 2019 (COVID-19) because of the immunological dysregulation and hyperinflammation associated with the condition. This study aimed to evaluate the potential risk factors for nosocomial bloodstream infections in hospitalized patients with COVID-19, including the exploration of corticosteroid dosage and treatment duration.

Materials and Methods

A retrospective cohort study of hospitalized patients with COVID-19 was conducted in a tertiary care hospital. We performed univariate and multivariate analyses of various parameters to identify risk factors for nosocomial bloodstream infection.

Results

Of 252 patients, 19% had nosocomial bloodstream infections. The mortality rate of nosocomial bloodstream infections was 62.5%. Multivariate analysis revealed that male sex (odds ratio [OR] 3.43; 95% confidence interval [CI]: 1.60-7.33), receiving methylprednisolone (OR: 3.01; 95% CI: 1.24-7.31), receiving an equivalent dexamethasone dose of 6-12 mg/day (OR: 7.49; 95% CI: 2.08-26.94), and leukocytosis on admission (OR: 4.13; 95% CI: 1.89-9.01) were significant predictors of nosocomial bloodstream infections.

Conclusion

Unmodified risk variables for nosocomial bloodstream infections included male sex and leukocytosis at admission. Using methylprednisolone and obtaining a cumulative dosage of dexamethasone were adjusted risk variables associated with superimposed nosocomial bloodstream infections in hospitalized patients with COVID-19.

Interactions between Gender and Sepsis—Implications for the Future

Sex and gender dimorphisms are found in a large variety of diseases, including sepsis and septic shock which are more prevalent in men than in women. Animal models show that the host response to pathogens differs in females and males. This difference is partially explained by sex polarization of the intracellular pathways responding to pathogen–cell receptor interactions. Sex hormones seem to be responsible for this polarization, although other factors, such as chromosomal effects, have yet to be investigated. In brief, females are less susceptible to sepsis and seem to recover more effectively than males. Clinical observations produce more nuanced findings, but men consistently have a higher incidence of sepsis, and some reports also claim higher mortality rates. However, variables other than hormonal differences complicate the interaction between sex and sepsis, including comorbidities as well as social and cultural differences between men and women. Conflicting data have also been reported regarding sepsis-attributable mortality rates among pregnant women, compared with non-pregnant females. We believe that unraveling sex differences in the host response to sepsis and its treatment could be the first step in personalized, phenotype-based management of patients with sepsis and septic shock.

Direct and indirect effects of socioeconomic status on sepsis risk and mortality: a mediation analysis of the HUNT Study

BACKGROUND

Socioeconomic status (SES) may influence risk of sepsis and sepsis-related mortality, but to what extent lifestyle and health-related factors mediate this effect is not known.

METHODS

The study included 65 227 participants of the population-based HUNT Study in Norway linked with hospital records to identify incident sepsis and sepsis-related deaths. Cox regression estimated HRs of sepsis risk and mortality associated with different indicators of SES, whereas mediation analyses were based on an inverse odds weighting approach.

RESULTS

During ~23 years of follow-up (1.3 million person-years), 4200 sepsis cases and 1277 sepsis-related deaths occurred. Overall, participants with low SES had a consistently increased sepsis risk and sepsis-related mortality using education, occupational class and financial difficulties as indicators of SES. Smoking and alcohol consumption explained 57% of the sepsis risk related to low education, whereas adding risk factors of cardiovascular disease and chronic diseases to the model increased the explained proportion to 78% and 82%, respectively.

CONCLUSION

This study shows that SES is inversely associated with sepsis risk and mortality. Approximately 80% of the effect of education on sepsis risk was explained by modifiable lifestyle and health-related factors that could be targets for prevention.

Insomnia symptoms and risk of bloodstream infections: prospective data from the prospective population-based Nord-Trøndelag Health Study (HUNT), Norway

Previous research suggests decreased immune function and increased risk of infections in individuals with insomnia. We examined the effect of insomnia symptoms on risk of bloodstream infections (BSIs) and BSI-related mortality in a population-based prospective study. A total of 53,536 participants in the second Norwegian Nord-Trøndelag Health Study (HUNT2) (1995-97) were linked to prospective data on clinically relevant BSIs until 2011. In Cox regression, we estimated hazard ratios (HRs) with 95% confidence intervals (CIs) for a first-time BSI and for BSI-related mortality (BSI registered ≤30 days prior to death) associated with insomnia symptoms. Compared with participants who reported "no symptoms", participants reporting having "difficulty initiating sleep" (DIS) often/almost every night had a HR for a first-time BSI of 1.14 (95% CI 0.96-1.34). Participants reporting "difficulties maintaining sleep" (DMS) often/almost every night had a HR of 1.19 (95% CI 1.01-1.40), whereas those having a feeling of "non-restorative sleep" once a week or more had a HR of 1.23 (95% CI 1.04-1.46). Participants frequently experiencing all three of the above symptoms had a HR of 1.39 (1.04-1.87), whilst those who had both DIS and DMS had a HR of 1.15 (0.93-1.41) and being troubled by insomnia symptoms to a degree that affected work performance was associated with a HR of 1.41 (95% CI 1.08-1.84). The HRs for BSI-related mortality suggest an increased risk with increasing insomnia symptoms, but the CIs are wide and inconclusive. We found that frequent insomnia symptoms and insomnia symptoms that affected work performance were associated with a weak positive increased risk of BSI.

Comparison of Length of Hospital Stay for Community-Acquired Infections Due to Enteric Pathogens, Influenza Viruses and Multidrug-Resistant Bacteria: A Cross-Sectional Study in Hungary

Community-acquired infections (CAI) can affect the duration of care and mortality of patients. Therefore, we aimed to investigate these as well as factors influencing the length of hospital stay in patients with CAI due to enteric pathogens, influenza viruses and multidrug-resistant (MDR) bacteria. We obtained data on 531 patients with CAI from the medical databases of a Hungarian university hospital and analyzed their characteristics using a regression model. Patients with MDR bacterial infection had the highest mortality (26.24%) and they stayed significantly longer in the hospital than cases with other CAIs. Our results showed that infection by Clostridioides difficile (odds ratio (OR): 6.98, 95% confidence interval (CI): 1.03-47.48; p = 0.047), MDR Escherichia coli (OR: 7.64, 95% CI: 1.24-47.17; p = 0.029), MDR Klebsiella spp. (OR: 7.35, 95% CI: 1.15-47.07; p = 0.035) and hospitalization in the department of pulmonology (OR: 5.48, 95% CI: 1.38-21.76; p = 0.016) and surgery (OR: 4.19, 95% CI: 1.18-14.81; p = 0.026) significantly increased, whereas female sex (OR: 0.62, 95% CI: 0.40-0.97; p = 0.037) and hospitalization in the department of pediatrics (OR: 0.17, 95% CI: 0.04-0.64; p = 0.009) decreased the odds of staying in the hospital for more than 6 days. Our findings provide new information on the epidemiology of CAI and can contribute to the development of public health programs that decrease the burden of infections acquired in the community.

Iron status and the risk of sepsis and severe COVID-19: a two-sample Mendelian randomization study

Observational studies have indicated an association between iron status and risk of sepsis and COVID-19. We estimated the effect of genetically-predicted iron biomarkers on risk of sepsis and risk of being hospitalized with COVID-19, performing a two-sample Mendelian randomization study. For risk of sepsis, one standard deviation increase in genetically-predicted serum iron was associated with odds ratio (OR) of 1.14 (95% confidence interval [CI] 1.01-1.29, P = 0.031). The findings were supported in the analyses for transferrin saturation and total iron binding capacity, while the estimate for ferritin was inconclusive. We found a tendency of higher risk of hospitalization with COVID-19 for serum iron; OR 1.29 (CI 0.97-1.72, P = 0.08), whereas sex-stratified analyses showed OR 1.63 (CI 0.94-2.86, P = 0.09) for women and OR 1.21 (CI 0.92-1.62, P = 0.17) for men. Sensitivity analyses supported the main findings and did not suggest bias due to pleiotropy. Our findings suggest a causal effect of genetically-predicted higher iron status and risk of hospitalization due to sepsis and indications of an increased risk of being hospitalized with COVID-19. These findings warrant further studies to assess iron status in relation to severe infections, including the potential of improved management.