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Daily Report

Daily Sepsis Research Analysis

10/16/2025
3 papers selected
3 analyzed

Three studies advance sepsis science and practice: a secondary analysis of two RCTs shows that phenotype-based subgrouping does not reliably personalize treatment benefits for sepsis resuscitation; a national cohort from England and Wales reveals very rapid mortality in invasive group A streptococcal infections, emphasizing pre-culture diagnostics; and an Australian multi-hospital validation demonstrates poor PPV of ICD-based algorithms for hospital-onset bloodstream infection, improved by remov

Summary

Three studies advance sepsis science and practice: a secondary analysis of two RCTs shows that phenotype-based subgrouping does not reliably personalize treatment benefits for sepsis resuscitation; a national cohort from England and Wales reveals very rapid mortality in invasive group A streptococcal infections, emphasizing pre-culture diagnostics; and an Australian multi-hospital validation demonstrates poor PPV of ICD-based algorithms for hospital-onset bloodstream infection, improved by removing unspecified sepsis codes.

Research Themes

  • Limits of phenotype-based precision medicine in sepsis resuscitation
  • Rapid lethality in invasive GAS sepsis and the need for pre-culture diagnostics
  • Improving surveillance accuracy: refining ICD-based detection of hospital-onset bloodstream infections

Selected Articles

1. Relationship Between Phenotyping and Individualized Absolute Risk Differences in Sepsis: A Secondary Analysis of Two Approaches in Two Multicenter Trials.

70Level IIRCT
Critical care explorations · 2025PMID: 41098209

Using data from the ProCESS and ARISE randomized trials, supervised models estimating individualized absolute risk differences showed wide within-subgroup variability in the effect of early goal-directed therapy. Even where average effects suggested benefit (β or nonhyperinflammatory) or harm (γ or hyperinflammatory), many individuals were predicted to experience the opposite effect.

Impact: This study challenges the assumption that phenotype-based subgrouping can reliably personalize sepsis resuscitation and introduces individualized absolute risk modeling as a superior approach to estimate treatment effects.

Clinical Implications: Clinicians should be cautious about deploying phenotype-restricted protocols for sepsis resuscitation and consider individualized risk modeling where feasible. Future trials should randomize or stratify based on predicted individualized benefit rather than phenotype alone.

Key Findings

  • Average EGDT effects differed by clinical (α, β, γ, δ) and biologic (hyperinflammatory vs nonhyperinflammatory) subphenotypes.
  • Within-subgroup iARDs ranged from substantial harm to benefit; in the β subtype, average mortality reduction was 8.5% (95% CI, -0.4 to 17.5) but 39% of patients were predicted to be harmed.
  • Phenotype-based subgrouping did not reliably identify individuals who would benefit from EGDT.

Methodological Strengths

  • Secondary analysis of two large multicenter RCTs (ProCESS and ARISE) with standardized outcomes
  • Use of supervised effect modeling to estimate individualized absolute risk differences with internal validation

Limitations

  • Post hoc modeling susceptible to overfitting and residual confounding despite randomization in source trials
  • Biomarker-based subphenotypes available only in a subset; generalizability beyond EGDT context is uncertain

Future Directions: Prospective trials that randomize based on predicted individualized benefit; integration of multi-omics and real-time data to refine iARD models; external validation across diverse settings.

OBJECTIVES: Sepsis trials likely include patients who vary in response to therapeutic interventions. The optimal approach to identify such differences in treatment response remains unclear. Estimating individualized absolute risk differences (iARDs) to model treatment response at an individual patient level using supervised effect models applied to randomized trial data may be informative. We explored the relationship between two subgrouping approaches and a recently published iARD model for the effect of early goal-directed therapy (EGDT) resuscitation in sepsis. DESIGN: Secondary analysis of the Protocolized Care for Early Septic Shock (ProCESS) and Australasian Resuscitation in Sepsis Evaluation (ARISE) trials. We applied clinical subtypes (α, β, γ, δ) to 829 ProCESS and 1588 ARISE patients and biologic "hyperinflammatory" and "nonhyperinflammatory" subphenotypes to 363 ProCESS patients with biomarker data using established methods. We predicted iARDs with supervised learning using clinical variables as predictors and 90-day mortality as the primary outcome. We evaluated iARD variability within subgroups. SETTING: Eighty-one sites worldwide. PATIENTS/SUBJECTS: Adults with septic shock. INTERVENTIONS: EGDT or usual care. MEASUREMENTS AND MAIN RESULTS: The average treatment effect of EGDT appeared to vary within both clinical and biologic subphenotypes. EGDT appeared potentially beneficial in the β and nonhyperinflammatory subphenotypes but harmful in the γ and hyperinflammatory subphenotypes. However, the predicted iARDs within each subgroup ranged from considerable harm to considerable benefit. For example, for the β-subtype, the average mortality reduction from EGDT was 8.5% (95% CI, -0.4 to 17.5), but the iARDs ranged from a 29% increase to a 16% reduction in mortality, with 39% of patients predicted to be harmed. CONCLUSIONS: Although both clinical and biologic phenotyping may identify subgroups whose average treatment effect is beneficial or harmful, individual risks and benefits within subgroups still vary dramatically, raising concern that phenotyping may not reliably or safely personalize sepsis care.

2. Mortality Among Patients With Invasive Group A Streptococcal Infections Caused by the M1UK Lineage: A Retrospective Cohort Study in England and Wales.

68.5Level IIICohort
Clinical infectious diseases : an official publication of the Infectious Diseases Society of America · 2025PMID: 41099520

In a national cohort of 4952 emm1 iGAS cases, 30-day case fatality rates were high and similar between M1UK and M1global lineages after adjustment. Notably, 63.7% of deaths occurred within one day of diagnostic sampling and most pediatric deaths occurred at or before sampling.

Impact: This study provides large-scale, lineage-resolved mortality data and highlights the ultra-rapid lethality of emm1 iGAS, shaping priorities for pre-culture diagnostics and prevention policies.

Clinical Implications: Clinicians should prioritize early recognition and empiric therapy for suspected iGAS, supported by rapid molecular diagnostics where available. Public health strategies should emphasize prevention and prehospital recognition, and trial designs must account for the narrow therapeutic window.

Key Findings

  • 30-day CFR: M1UK 24.4%, M1global 22.3%, M123SNP 10.5%, M113SNP 10.3%.
  • After age and sex adjustment, lineage was not a significant predictor of 7- or 30-day mortality.
  • 63.7% of deaths occurred within 1 day of diagnostic sampling; among children <15 years, 56.3% died before sampling and 95.6% within 1 day of sampling.

Methodological Strengths

  • Large national linked dataset over 12+ years with lineage assignment via WGS or allele-specific PCR
  • Adjusted analyses and time-to-event evaluation highlighting clinical timelines

Limitations

  • Lineage assignment available for a subset (1356/4952), potentially introducing selection bias
  • Unmeasured confounders (e.g., time to antibiotics, source control) and limited clinical covariates

Future Directions: Implement rapid pre-culture diagnostics and evaluate their impact on outcomes; assess vaccine or prophylaxis strategies; incorporate ultra-early endpoints in iGAS trials.

BACKGROUND: The M1UK sublineage of Streptococcus pyogenes has driven recent post-pandemic surges in invasive group A streptococcal (iGAS) disease. We assessed case fatality rate (CFR) among patients with emm1 iGAS in England and Wales, and then compared outcomes associated with M1UK and ancestral emm1 lineages. METHODS: We linked emm1 iGAS cases (December 2009-July 2022) with demographic and mortality records. Lineage was determined for isolates collected in 2010, 2013-2016, and 2020 via whole-genome sequencing or allele-specific PCR. Seven- and 30-day all-cause CFRs were estimated. Univariate and multivariate models assessed the association between lineage and risk of death. RESULTS: Among 4952 emm1 iGAS cases, lineage was assigned to 1356. The 30-day CFR was 24.4% for M1UK, 22.3% for M1global, 10.5% for M123SNP, and 10.3% for M113SNP. After adjustment for age and sex, lineage was not a significant predictor of 7- or 30-day mortality. Survival analysis showed rapid progression to death in both M1UK and M1global cases: 63.7% of deaths occurred within 1 day of diagnostic sampling. Among children under 15 years, 56.3% of fatal cases died before sampling, and 95.6% within 1 day of sampling. CONCLUSIONS: Mortality did not differ significantly between M1UK and M1global lineages, but more studies are required. Overall mortality from emm1 S. pyogenes remains strikingly high. The rapid time to death underscores the need for preventive measures and rapid diagnostic tools that act prior to culture-based confirmation, and highlights challenges for clinical trial design in iGAS.

3. Performance of the Australian hospital-acquired complication algorithm for detecting hospital-onset bloodstream infections.

62.5Level IIICohort
Infection, disease & health · 2025PMID: 41093736

Across five Australian hospitals, the ICD-based HAC algorithm had a PPV of 0.28 and NPV of 1.00 for hospital-onset bloodstream infection. Unspecified sepsis codes were major false-positive drivers; removing them increased PPV to 0.53.

Impact: This study provides actionable refinements to administrative algorithms that influence surveillance, quality metrics, and reimbursement for sepsis-related complications.

Clinical Implications: Hospitals should not rely solely on ICD-based HAC flags for HO-BSI; integrate laboratory-confirmed surveillance and consider excluding unspecified sepsis codes to improve accuracy of quality reporting.

Key Findings

  • PPV 0.28 (95% CI 0.23–0.34) and NPV 1.00 (95% CI 0.98–1.00) for HO-BSI detection by the HAC algorithm.
  • Unspecified sepsis ICD codes accounted for 35.8% (sepsis, unspecified) and 18.4% (newborn bacterial sepsis, unspecified) of HO-BSI flags with very poor PPV (0.06 and 0.03).
  • Removing unspecified sepsis codes increased PPV to 0.53 (95% CI 0.45–0.62).

Methodological Strengths

  • Multicenter evaluation with blinded manual adjudication against surveillance definitions
  • Large administrative dataset (352,917 episodes) and iterative algorithm testing

Limitations

  • Manual review sample size was limited (50 positives and 50 negatives per site)
  • Findings may be specific to Australian coding practices and the 2016–2017 period

Future Directions: Validate refined algorithms nationally; integrate microbiology, timing of blood cultures, and NLP from clinical notes; assess impact on quality metrics and incentives.

BACKGROUND: The Australian Commission on Safety and Quality in Healthcare developed a list of sixteen potentially preventable Hospital-Acquired Complications (HACs) and an algorithm using International Classification of Disease (ICD) codes to detect them. We evaluated this algorithm's performance for diagnosing hospital-onset bloodstream infections (HO-BSI). METHODS: Administrative records were extracted for episodes of admitted patient care from July 2016 to June 2017 at five Australian principal referral hospitals. We applied the BSI HAC algorithm to each episode, then randomly selected 50 patients deemed positive and negative for HO-BSI at each site. Reviewers blinded to HAC status applied the reference surveillance definition for HO-BSI. The positive predictive value (PPV) and negative predictive value (NPV) for the BSI HAC were calculated. We explored changes to the HAC algorithm to improve these metrics. RESULTS: Overall, 352 917 episodes were included; median (IQR) age was 54 (33-71) years, 49.6 % were female, and 43.8 % were elective admissions. Of these, 2229 (0.6 %) had a HO-BSI according to the HAC algorithm. Among manually reviewed episodes, the PPV for the HAC algorithm was 0.28 (95 % CI, 0.23-0.34) and the NPV was 1.00 (95 % CI, 0.98-1.00). The codes 'Sepsis, unspecified' and 'bacterial sepsis of newborn, unspecified' were both common triggers for HO-BSI HACs (accounting for 35.8 % and 18.4 % of HO-BSIs, respectively) and had poor PPV (0.06 and 0.03, respectively). Removal of these codes from the algorithm increased PPV to 0.53 (0.45-0.62). CONCLUSION: The HAC algorithm had sub-optimal PPV for HO-BSI. This performance was improved by removing the 'unspecified sepsis' ICD codes.