Daily Sepsis Research Analysis
Three impactful studies advance sepsis science along complementary axes: a multi-institutional, FHIR-enabled Python implementation of the SENECA algorithm demonstrates feasible, reproducible sepsis subtyping; a Mendelian randomization analysis implicates waist circumference as a causal risk factor for sepsis susceptibility and mortality; and a 12-year prospective cohort delineates pneumonia-source sepsis epidemiology, identifying nosocomial origin as a dominant mortality predictor.
Summary
Three impactful studies advance sepsis science along complementary axes: a multi-institutional, FHIR-enabled Python implementation of the SENECA algorithm demonstrates feasible, reproducible sepsis subtyping; a Mendelian randomization analysis implicates waist circumference as a causal risk factor for sepsis susceptibility and mortality; and a 12-year prospective cohort delineates pneumonia-source sepsis epidemiology, identifying nosocomial origin as a dominant mortality predictor.
Research Themes
- Interoperable informatics for sepsis subtyping and trial enrichment
- Genetic causal inference linking adiposity to infection risk
- Long-term epidemiology and prognostic factors in pneumonia-source sepsis
Selected Articles
1. A FHIR-Powered Python Implementation of the SENECA Algorithm for Sepsis Subtyping.
Using FHIR resources from two health systems, a Python implementation of the SENECA sepsis subtyping algorithm successfully classified sepsis subtypes with concordance to the original R implementation. Differences between RDW- and EHR-derived FHIR APIs and prevalent missingness were highlighted, and open-source code was released to facilitate multi-institutional trial enrichment.
Impact: Provides an interoperable, open-source pipeline for prerandomization sepsis subtyping, enabling precision trial design across health systems. Addresses a key barrier to translating endotypes into actionable clinical research.
Clinical Implications: Enables real-time or near-real-time sepsis endotyping and trial enrichment across sites, potentially improving patient stratification and therapeutic signal detection. Highlights the need to standardize FHIR queries and handle missingness.
Key Findings
- A Python SENECA implementation achieved successful sepsis subtyping at two academic centers using FHIR resources.
- Concordance was demonstrated between the new Python and the original R implementations.
- Discrepancies arose between RDW-derived and EHR-integrated FHIR APIs due to query/filtering limitations.
- Missing data were common and influenced by both clinical practice patterns and FHIR API constraints.
- Open-source code and five recommendations were provided to guide multi-institutional deployment.
Methodological Strengths
- Cross-institutional validation with concordance to an independent implementation
- Interoperable, standards-based (FHIR) data extraction with open-source reproducibility
Limitations
- Feasibility study limited to two centers and 765 encounters
- Data quality and missingness heavily influenced by local FHIR APIs and clinical workflows
Future Directions: Standardize FHIR query profiles, expand to more sites, integrate real-time pipelines, and prospectively test subtype-guided trial enrichment and clinical decision support.
Sepsis is a heterogeneous syndrome with high morbidity and mortality. Despite extensive clinical trials, therapeutic progress remains limited, in part due to the absence of actionable sepsis subtypes.This study aimed to evaluate the feasibility of using HL7 Fast Healthcare Interoperability Resources (FHIR) for prerandomization sepsis subtyping to support clinical trial enrichment across multiple health systems.Data from 765 encounters at two academic medical centers were analyzed. FHIR-based resources were extracted from both research data warehouses (RDWs) and electronic health records (EHRs). A Python implementation of the Sepsis Endotyping in Emergency Care (SENECA) sepsis subtyping algorithm was developed to query and assemble FHIR resources for subtype classification.Open-source Python code for the SENECA algorithm is provided on GitHub. Experiments demonstrated: (1) successful sepsis subtyping across both health systems; (2) concordance between the original R implementation and the new Python implementation; and (3) discrepancies when comparing RDW-derived versus EHR-integrated FHIR APIs, primarily due to query and filtering limitations. Missing data were common and influenced by both clinical practice and FHIR API constraints. We provide five recommendations to address these challenges.FHIR can support multi-institutional sepsis subtyping and trial enrichment, though technical and governance challenges remain.
2. Causal association between 3 adiposity indices and 5 infectious diseases: A Mendelian randomization study.
Across multiple biobanks, multivariable Mendelian randomization identified waist circumference—not BMI or hip circumference—as causally associated with sepsis susceptibility (OR 1.95) and sepsis mortality (OR 3.23), as well as cholecystitis and skin/subcutaneous infections. Robust sensitivity analyses suggested no pleiotropy or reverse causation.
Impact: Provides genetic causal evidence linking central adiposity to sepsis susceptibility and mortality, elevating waist circumference as a modifiable prevention target across populations.
Clinical Implications: Prioritize waist circumference measurement in risk assessments and prevention strategies; inform public health interventions targeting central adiposity to reduce sepsis burden.
Key Findings
- Only waist circumference showed a significant, independent causal association with sepsis susceptibility (OR 1.95, 95% CI 1.41–2.69) and sepsis mortality (OR 3.23, 95% CI 1.52–6.86).
- No causal effects were detected for BMI or hip circumference on the infectious outcomes after multivariable adjustment.
- Results were robust across multiple MR methods with Bonferroni correction; no pleiotropy or reverse causality detected.
- Waist circumference was also causally linked to cholecystitis and skin/subcutaneous tissue infections.
Methodological Strengths
- Use of multivariable MR across multiple large biobanks with Bonferroni correction
- Comprehensive sensitivity analyses (IVW, LASSO, MVMR-robust) with pleiotropy and reverse-causation checks
Limitations
- MR relies on instrument validity and assumes no residual pleiotropy; measurement heterogeneity across cohorts is possible
- Summary-level data limit assessment of subgroup effects and dynamic changes in adiposity over time
Future Directions: Prospective interventional studies targeting central adiposity reduction to evaluate effects on sepsis incidence and outcomes; exploration of mechanistic pathways linking visceral adiposity to host response.
Previous studies on the association between adiposity indices and risk of infection have been inconsistent. To investigate the causality between different adiposity indices (body mass index [BMI], waist circumference [WC], and hip circumference [HC]) and the risk of infection (sepsis susceptibility (SS), sepsis mortality (SM), cholecystitis, intestinal infections, infections of the skin and subcutaneous tissue [SSTI], and acute lower respiratory infections). Mendelian randomization (MR) analysis was conducted to explore the causality between the 3 adiposity indices and the risk of 5 infectious diseases. Twenty-eight MR analyses were conducted to evaluate the final results, comprising 18 forward univariate MR, 5 reverse univariate MR, and 5 multivariable MR (MVMR) analyses. Data on adiposity indices and infections were obtained from the UK Biobanks, FinnGen Biobanks, Medical Research Council Integrative Epidemiology Unit, and within the family genome-wide association study consortium. Preliminary genetic variants associated with BMI (n = 11), WC (n = 374), and HC (n = 420) were selected as instrumental variables. The inverse-variance weighted (IVW) method combined with different types of MR methods was used to enhance the robustness of the final results. The statistical significance threshold was corrected using the Bonferroni method. The MVMR-IVW (random) analysis revealed that only WC had a significant and independent causal association with SS (odds ratio [OR] = 1.95; 95% confidence interval [CI]: 1.41-2.69; P < .001), SM (OR = 3.23; 95% CI: 1.52-6.86; P = .002), cholecystitis (OR = 1.87; 95% CI: 1.36-2.55; P < .001), and SSTI (OR = 1.74; 95% CI: 1.26-2.41; P = .001). These results were confirmed by other MVMR methods (least absolute shrinkage and selection operator regression, and MVMR-robust). Neither pleiotropy nor reverse causality was detected. WC may predict infectious disease risk more efficiently than other indices, and controlling WC may help decrease the risk of infectious diseases. Future long-term prospective studies are needed to explore the associations between dynamic adiposity indices and diverse infectious diseases in different populations.
3. Respiratory sepsis: a 12-year prospective observational study in critically ill patients.
In a 12-year ICU sepsis registry (n=2116), 590 cases had pneumonia as the source; hospital-acquired pneumonia was less common than CAP but more severe and independently predicted mortality. CAP was dominated by Streptococcus pneumoniae, whereas HAP frequently involved E. coli and P. aeruginosa.
Impact: Provides long-term, prospective epidemiology and prognostic factors specific to pneumonia-source sepsis, highlighting nosocomial origin as the dominant mortality driver.
Clinical Implications: Emphasizes early recognition and aggressive management of nosocomial pneumonia in sepsis pathways, with attention to thrombocytopenia, hypoglycemia, and need for MV/RRT as high-risk markers.
Key Findings
- Among 2116 ICU sepsis cases, 590 (27.9%) were respiratory-source; 73.6% CAP and 26.4% HAP.
- HAP had higher severity (APACHE II/SOFA), more hemodynamic instability, thrombocytopenia, and greater use of vasopressors, MV, and RRT.
- ICU mortality was 24.7% and hospital mortality 33.7%, both higher in HAP.
- Nosocomial origin was the strongest independent predictor of mortality; additional predictors included thrombocytopenia, hypoglycemia, need for MV/RRT, higher APACHE II, and admission lactate.
Methodological Strengths
- Prospective design over 12 years with a dedicated sepsis registry
- Detailed microbiology and multivariable modeling of mortality predictors
Limitations
- Single-center study may limit generalizability
- No intervention; residual confounding and practice changes over time are possible
Future Directions: Multi-center validation of nosocomial-origin risk models, and interventional studies targeting early HAP detection and optimized antimicrobial/organ support strategies.
BACKGROUND: Pneumonia is the leading source of sepsis worldwide and remains associated with high morbidity and mortality. However, prospective long-term studies specifically describing the clinical characteristics, microbiology, and outcomes of patients with respiratory-source sepsis are scarce. METHODS: We conducted a 12-year prospective observational study (January 1, 2012-December 31, 2023) at the Department of Intensive Care Medicine, Donostia University Hospital, the only tertiary care center in Gipuzkoa, Spain. All adult ICU patients with sepsis or septic shock were included; this analysis focused on those with pneumonia as the infection source. Demographic and clinical features, microbiology, management, and prognostic factors for mortality were analyzed. RESULTS: Our sepsis registry included 2116 ICU patients with sepsis or septic shock; pneumonia was identified as the infectious source in 590 cases (27.9 %), of which 434 (73.6 %) were community-acquired (CAP) and 156 (26.4 %) hospital-acquired (HAP), including 19 ventilator-associated pneumonia (VAP). Compared with CAP, HAP patients had higher APACHE II and SOFA scores, more frequent hemodynamic instability and thrombocytopenia, and greater need for vasoactive support, mechanical ventilation (MV), and renal replacement therapy (RRT). No significant differences were observed in sex, age, or admission levels of procalcitonin and lactate. Streptococcus pneumoniae predominated in CAP, whereas Escherichia coli and Pseudomonas aeruginosa were most common in HAP. ICU mortality was 24.7 % and overall hospital mortality 33.7 %, both higher in HAP. Multivariate analysis identified nosocomial origin as the strongest independent predictor of mortality, along with thrombocytopenia, hypoglycemia, need for MV and RRT, higher APACHE II, and lactate at admission. CONCLUSIONS: Within our prospective sepsis registry, pneumonia was the most frequent infectious source. Nosocomial pneumonia, although less common than CAP, was associated with greater severity and emerged as the main independent predictor of mortality.