Influence of the National Trauma Data Bank on the study of trauma outcomes: is it time to set research best practices to further enhance its impact?

Abstract

Background: Risk-adjusted analyses are critical in evaluating trauma outcomes. The National Trauma Data Bank (NTDB) is a statistically robust registry that allows such analyses; however, analytical techniques are not yet standardized. In this study, we examined peer-reviewed manuscripts published using NTDB data, with particular attention to characteristics strongly associated with trauma outcomes. Our objective was to determine if there are substantial variations in the methodology and quality of risk-adjusted analyses and therefore, whether development of best practices for risk-adjusted analyses is warranted.

Study design: A database of all studies using NTDB data published through December 2010 was created by searching PubMed and Embase. Studies with multivariate risk-adjusted analyses were examined for their central question, main outcomes measures, analytical techniques, covariates in adjusted analyses, and handling of missing data.

Results: Of 286 NTDB publications, 122 performed a multivariable adjusted analysis. These studies focused on clinical outcomes (51 studies), public health policy or injury prevention (30), quality (16), disparities (15), trauma center designation (6), or scoring systems (4). Mortality was the main outcome in 98 of these studies. There were considerable differences in the covariates used for case adjustment. The 3 covariates most frequently controlled for were age (95%), Injury Severity Score (85%), and sex (78%). Up to 43% of studies did not control for the 5 basic covariates necessary to conduct a risk-adjusted analysis of trauma mortality. Less than 10% of studies used clustering to adjust for facility differences or imputation to handle missing data.

Conclusions: There is significant variability in how risk-adjusted analyses using data from the NTDB are performed. Best practices are needed to further improve the quality of research from the NTDB.

Figure 1

Temporal distribution of published studies utilizing the NTDB (n=122).

Figure 2

Distribution of papers utilizing the NTDB in various medical journals (n=122). *Others include: Prehosp Disaster Med, Acad Emerg Med, J Pediatr Surg, Bull NYU Hosp Jt Dis, Burns, Critical Care Medicine, Injury, J Bone Joint Surg, Am J Pediatr Surg, J Urol, World J Surg, Health Policy, Inj Prev, J Burn Care Rehab, J Clin Nurs, JAAPA, Med Care, Mol Med, Pediatr Crit Care Med, Shock, Surg Infect, J Natl Med Assoc etc.

Figure 3

Adjusted outcome measures studied utilizing the NTDB (n=122). LOS – length of stay, Et-OH- alcohol, VTE – venous thromboembolism (deep venous thrombosis and/or pulmonary embolism), VCF – vena caval filters, BIAI – blunt iliac artery injury, TBI traumatic brain injury.

Figure 4

Ten most frequently used covariates adjusted for in trauma mortality outcomes (n=98). ISS – injury severity score, SBP – systolic blood pressure in the emergency department (shock), GCS-T – Glasgow Coma Score – total, MOI – mechanism of injury (motor vehicle crash, fall, pedestrian struck, etc), Head AIS - head abbreviated injury score, Type – type of injury (blunt vs penetrating).

Figure 5

Most frequently used covariates to adjust for trauma mortality outcomes after additional grouping of variables (n=98). MOI (Mechanism of injury) includes controlling for different mechanisms such motor vehicle crash, fall, pedestrian struck, etc or Type of injury (blunt vs. penetrating); Physiologic severity includes controlling for any: Systolic blood pressure (SBP), Revised Trauma Score (RTS), Respiratory Rate (RR), Heart Rate (HR), Trauma and Injury Severity Score (TRISS), and Base Deficit (BD); Anatomy severity includes: ISS, New ISS (NISS), Anatomic Profile (AP), TRISS, Abbreviated Injury Score (AIS) for every region; Head injury includes adjusting for: Head AIS, Glasgow Coma Scores (GCS) of its components or Head CT scan.

Figure 6

Percentage of papers adjusting for as little as 1 to all 5 for the “bare minimum” covariates thought to be essential while performing a risk-adjusted analysis with trauma mortality as the outcome. All 5 co-variates: 1) Mechanism of injury [includes controlling for different mechanisms, such as motor vehicle crash, fall, pedestrian struck, etc., or controlling for type of injury (blunt vs. penetrating)]; 2) Physiologic severity (includes controlling for any of the following: Systolic blood pressure, Revised Trauma Score, Respiratory Rate, Heart Rate, Trauma and Injury Severity Score, or Base Deficit) 3) Anatomy severity (includes: ISS, New ISS, Anatomic Profile (AP), TRISS, Abbreviated Injury Score for any region) 4) Age and 5) Sex. *n for 5 co-variates = 56; n for 4 co-variates = 29; n for 3 co-variates = 8; n for 2 co-variates = 4; n for 1 co-variate = 1.