What is the utility of delta shock index (DSI) in predicting mortality and clinical outcome in trauma patients in developed vs developing countries?

Research Proposal for Delta Shock Index in Predicting Mortality and Clinical Outcomes in Developed vs Developing Countries

Background and Rationale

Delta Shock Index (DSI) is a superior predictor of mortality and clinical outcomes in trauma patients compared to traditional vital signs and should be incorporated into trauma assessment protocols in both developed and developing countries. 1

DSI, defined as the change in Shock Index (heart rate/systolic blood pressure) over time, has emerged as a valuable prognostic tool in trauma care. While traditional vital signs may be unreliable, particularly in elderly patients or those on medications affecting hemodynamic responses, DSI provides a more dynamic assessment of a patient's physiological response to injury and resuscitation.

Research Aims

1. Compare the predictive ability of DSI for mortality and clinical outcomes between trauma patients in developed vs developing countries using the PATOS and Malaysia Trauma Registry
2. Identify optimal DSI thresholds for predicting adverse outcomes in different healthcare resource settings
3. Evaluate the impact of healthcare system factors on the utility of DSI in trauma management

Methodology

Study Design

• Multicenter, retrospective cohort study using data from:
  • PATOS (Pan-Asian Trauma Outcomes Study) database
  • Malaysia Trauma Registry
  • Comparative data from developed country trauma registries

Study Population

• Adult trauma patients (≥18 years) with complete vital sign documentation
• Stratification by:
  • Country development status (developed vs developing)
  • Age groups (special focus on elderly ≥65 years)
  • Injury severity (ISS categories)
  • Trauma mechanism (blunt vs penetrating)

Variables

1. Primary Exposure Variable:

   • Delta Shock Index (DSI) calculated as:
     • Prehospital DSI: Change between first and last prehospital SI
     • ED DSI: Change between ED arrival and ED discharge SI
     • Total DSI: Change between first prehospital and ED discharge SI

2. Primary Outcome Measures:

   • In-hospital mortality
   • 28-day mortality

3. Secondary Outcome Measures:

   • Need for blood transfusion within 4 hours
   • ICU admission
   • Hospital length of stay
   • Need for life-saving interventions
   • Ventilator days

4. Covariates:

   • Age, sex, comorbidities
   • Injury Severity Score (ISS)
   • Trauma mechanism
   • Prehospital time
   • Medications affecting vital signs (e.g., beta-blockers)
   • Hospital level (trauma center designation)
   • Country-specific healthcare resource availability

Statistical Analysis

1. Descriptive Statistics:

   • Baseline characteristics by country development status
   • Distribution of DSI values across different populations

2. Predictive Performance Analysis:

   • Area under the receiver operating characteristic curve (AUROC) for DSI in predicting outcomes
   • Comparison with traditional shock index, prehospital SI, ED SI
   • Comparison with established trauma scoring systems (ISS, TRISS, GTOS)

3. Threshold Determination:

   • Sensitivity, specificity, positive and negative predictive values for different DSI thresholds
   • Youden index to determine optimal DSI cutoff values by country development status

4. Multivariate Analysis:

   • Logistic regression models adjusting for confounders
   • Stratified analyses by country development status
   • Interaction analyses to identify effect modifiers

5. Healthcare System Analysis:

   • Correlation between healthcare resource availability and DSI predictive performance
   • Subgroup analyses by prehospital care quality metrics

Expected Outcomes

Based on current evidence, we anticipate:

• DSI will demonstrate strong predictive ability for mortality and resource utilization in both developed and developing countries 2, 3
• A DSI >0.1 will be associated with approximately 31% increased likelihood of death and 2x higher odds of requiring blood products 3
• The predictive performance of DSI may differ between developed and developing countries due to variations in:
  • Prehospital care quality and transport times
  • Hospital resource availability
  • Patient demographics and comorbidity profiles
• DSI may be particularly valuable in resource-limited settings where advanced diagnostic capabilities are limited 1

Practical Implications

This research will:

1. Establish the utility of DSI as a triage tool in different resource settings
2. Determine whether DSI thresholds should be adjusted based on country development status
3. Guide resource allocation in trauma systems with limited resources
4. Inform the development of context-specific trauma protocols

Potential Challenges and Solutions

1. Missing Data:

   • Multiple imputation techniques for handling missing vital signs
   • Sensitivity analyses comparing complete case analysis with imputed data

2. Variability in Data Collection:

   • Standardized data extraction protocols
   • Quality control checks for data consistency

3. Confounding Factors:

   • Propensity score matching to balance baseline characteristics
   • Stratified analyses by key confounders

4. Generalizability:

   • Include diverse trauma centers from multiple countries
   • Subgroup analyses by hospital resource levels

Timeline and Resources

• Data extraction and cleaning: 3 months
• Statistical analysis: 3 months
• Manuscript preparation: 2 months
• Dissemination of findings: Ongoing

Conclusion

This research proposal addresses a critical gap in trauma care knowledge by examining how the utility of Delta Shock Index varies between developed and developing countries. The findings will inform context-specific trauma protocols and potentially improve resource allocation in settings with limited healthcare resources.