Elliott R. Haut

Race and Insurance Status as Risk Factors for Trauma Mortality

OBJECTIVE To determine the effect of race and insurance status on trauma mortality. METHODS Review of patients (aged 18-64 years; Injury Severity Score > or = 9) included in the National Trauma Data Bank (2001-2005). African American and Hispanic patients were each compared with white patients and insured patients were compared with uninsured patients. Multiple logistic regression analyses determined differences in survival rates after adjusting for demographics, injury severity (Injury Severity Score and revised Trauma Score), severity of head and/or extremity injury, and injury mechanism. RESULTS A total of 429 751 patients met inclusion criteria. African American (n = 72,249) and Hispanic (n = 41,770) patients were less likely to be insured and more likely to sustain penetrating trauma than white patients (n = 262,878). African American and Hispanic patients had higher unadjusted mortality rates (white, 5.7%; African American, 8.2%; Hispanic, 9.1%; P = .05 for African American and Hispanic patients) and an increased adjusted odds ratio (OR) of death compared with white patients (African American OR, 1.17; 95% confidence interval [CI], 1.10-1.23; Hispanic OR, 1.47; 95% CI, 1.39-1.57). Insured patients (47%) had lower crude mortality rates than uninsured patients (4.4% vs 8.6%; P = .05). Insured African American and Hispanic patients had increased mortality rates compared with insured white patients. This effect worsened for uninsured patients across groups (insured African American OR, 1.2; 95% CI, 1.08-1.33; insured Hispanic OR, 1.51; 95% CI, 1.36-1.64; uninsured white OR, 1.55; 95% CI, 1.46-1.64; uninsured African American OR, 1.78; 95% CI, 1.65-1.90; uninsured Hispanic OR, 2.30; 95% CI, 2.13-2.49). The reference group was insured white patients. CONCLUSION Race and insurance status each independently predicts outcome disparities after trauma. African American, Hispanic, and uninsured patients have worse outcomes, but insurance status appears to have the stronger association with mortality after trauma.

Association Between Helicopter vs Ground Emergency Medical Services and Survival for Adults With Major Trauma

CONTEXT Helicopter emergency medical services and their possible effect on outcomes for traumatically injured patients remain a subject of debate. Because helicopter services are a limited and expensive resource, a methodologically rigorous investigation of its effectiveness compared with ground emergency medical services is warranted. OBJECTIVE To assess the association between the use of helicopter vs ground services and survival among adults with serious traumatic injuries. DESIGN, SETTING, AND PARTICIPANTS Retrospective cohort study involving 223,475 patients older than 15 years, having an injury severity score higher than 15, and sustaining blunt or penetrating trauma that required transport to US level I or II trauma centers and whose data were recorded in the 2007-2009 versions of the American College of Surgeons National Trauma Data Bank. INTERVENTIONS Transport by helicopter or ground emergency services to level I or level II trauma centers. MAIN OUTCOME MEASURES Survival to hospital discharge and discharge disposition. RESULTS A total of 61,909 patients were transported by helicopter and 161,566 patients were transported by ground. Overall, 7813 patients (12.6%) transported by helicopter died compared with 17,775 patients (11%) transported by ground services. Before propensity score matching, patients transported by helicopter to level I and level II trauma centers had higher Injury Severity Scores. In the propensity score-matched multivariable regression model, for patients transported to level I trauma centers, helicopter transport was associated with an improved odds of survival compared with ground transport (odds ratio [OR], 1.16; 95% CI, 1.14-1.17; P < .001; absolute risk reduction [ARR], 1.5%). For patients transported to level II trauma centers, helicopter transport was associated with an improved odds of survival (OR, 1.15; 95% CI, 1.13-1.17; P < .001; ARR, 1.4%). A greater proportion (18.2%) of those transported to level I trauma centers by helicopter were discharged to rehabilitation compared with 12.7% transported by ground services (P < .001), and 9.3% transported by helicopter were discharged to intermediate facilities compared with 6.5% by ground services (P < .001). Fewer patients transported by helicopter left level II trauma centers against medical advice (0.5% vs 1.0%, P < .001). CONCLUSION Among patients with major trauma admitted to level I or level II trauma centers, transport by helicopter compared with ground services was associated with improved survival to hospital discharge after controlling for multiple known confounders.

Surveillance Bias in Outcomes Reporting

THE PREVALENCE AND EXTENT OF PUBLIC REPORTING of adverse medical outcomes are increasing. Many private, public, and government Web sites rank hospitals and report scores on selected quality measures. Health care consumers, including referring physicians, individual patients, and insurers, can use these data to inform decision making by selecting hospitals with better outcomes. However, the science of outcome reporting is young and lags behind the desires of the public in this information age. Reporting quality measures may have benefits but also may pose risks from unintended consequences. When validating outcome measures, the main focus has been strict definitions for numerators to clearly identify cases and for denominators to identify patients at risk. Standardized surveillance for events within the population of those at risk has received little attention, and as a result, surveillance bias is likely an important source of error in currently reported outcome measures. Surveillance bias, a nonrandom type of information bias, refers to the idea that “the more you look, the more you find.” It occurs when some patients are followed up more closely or have more diagnostic tests performed than others, often leading to an outcome diagnosed more frequently in the more closely monitored group. In an article on biases inherent to clinical research, Sackett used the phrase “unmasking (detection signal) bias” to explain how “an innocent exposure may become suspect if, rather than causing a disease, it causes a sign or symptom which precipitates a search for the disease.” As a result, differences in outcomes may be related to surveillance bias rather than differences in quality. If ignored, flawed causal inferences could be suggested from differential rates identified between groups. Surveillance bias is a well-known concept in epidemiology yet is seldom considered in published clinical studies. For example, deep vein thrombosis (DVT) is a significant cause of preventable harm and a commonly monitored quality-of-care measure. DVT is a common, lifethreatening complication among patients who have sustained trauma. Because injured patients are at increased risk for DVT, some clinicians use duplex ultrasound to screen highrisk asymptomatic trauma patients for DVT. Other clinicians argue this approach is neither clinically necessary nor cost-effective and therefore do not routinely screen for DVT in trauma patients. This clinical uncertainly leads to variability in the use of screening duplex ultrasound, creating variability in rates of DVT identified and reported—a typical example of surveillance bias. Evidence for surveillance bias in DVT reporting after trauma is well documented. For instance, after implementation of a DVT screening guideline at one trauma center, duplex ultrasound rates increased 4-fold and DVT rates increased 10-fold. Within the National Trauma Data Bank, DVT rates were 7-fold higher at hospitals in the highest quartile of use of vascular ultrasound, and patients treated at hospitals that performed more duplex ultrasounds were twice as likely to have DVT reported, even controlling for other patient risk factors. Surveillance bias also is an important factor in other highprofile publicly reported outcome measures. For example, rates of central line–associated bloodstream infections (BSIs) increased 3-fold with the use of computer automated surveillance, suggesting that “surveillance practice may complicate interinstitutional comparisons of publicly reported central line–associated BSI rates.” The hazard of error caused by surveillance bias will likely increase with increasing use of penalties and rewards for performance on quality measures. Surveillance bias also has the potential to pose significant harms. For instance, patients may be harmed because clinicians will not know if quality of care is improving, and incentives to improve outcomes may encourage clinicians to avoid appropriate diagnostic testing to minimize reported complications. Because performance measures do not specify surveillance, outcomes that are not sought ordinarily will not be detected. This potential for unintended consequences was summarized in a comment by Alam and Velmahos as: “No screening, no DVT, no punishment.” Thus,

Evaluation of Surveillance Bias and the Validity of the Venous Thromboembolism Quality Measure

IMPORTANCE Postoperative venous thromboembolism (VTE) rates are widely reported quality metrics soon to be used in pay-for-performance programs. Surveillance bias occurs when some clinicians use imaging studies to detect VTE more frequently than other clinicians. Because they look more, they find more VTE events, paradoxically worsening their hospitals VTE quality measure performance. A surveillance bias may influence VTE measurement if (1) greater hospital VTE prophylaxis adherence fails to result in lower measured VTE rates, (2) hospitals with characteristics suggestive of higher quality (eg, more accreditations) have greater VTE prophylaxis adherence rates but worse VTE event rates, and (3) higher hospital VTE imaging utilization use rates are associated with higher measured VTE event rates. OBJECTIVE To examine whether a surveillance bias influences the validity of reported VTE rates. DESIGN, SETTING, AND PARTICIPANTS 2010 Hospital Compare and American Hospital Association data from 2838 hospitals were merged. Next, 2009-2010 Medicare claims data for 954,926 surgical patient discharges from 2786 hospitals who were undergoing 1 of 11 major operations were used to calculate VTE imaging (duplex ultrasonography, chest computed tomography/magnetic resonance imaging, and ventilation-perfusion scans) and VTE event rates. MAIN OUTCOMES AND MEASURES The association between hospital VTE prophylaxis adherence and risk-adjusted VTE event rates was examined. The relationship between a summary score of hospital structural characteristics reflecting quality (hospital size, numbers of accreditations/quality initiatives) and performance on VTE prophylaxis and risk-adjusted VTE measures was examined. Hospital-level VTE event rates were compared across VTE diagnostic imaging rate quartiles and with a quantile regression. RESULTS Greater hospital VTE prophylaxis adherence rates were weakly associated with worse risk-adjusted VTE event rates (r2 = 4.2%; P = .03). Hospitals with increasing structural quality scores had higher VTE prophylaxis adherence rates (93.3% vs 95.5%, lowest vs highest quality quartile; P < .001) but worse risk-adjusted VTE rates (4.8 vs 6.4 per 1000, lowest vs highest quality quartile; P < .001). Mean VTE diagnostic imaging rates ranged from 32 studies per 1000 in the lowest imaging use quartile to 167 per 1000 in the highest quartile (P < .001). Risk-adjusted VTE rates increased significantly with VTE imaging use rates in a stepwise fashion, from 5.0 per 1000 in the lowest quartile to 13.5 per 1000 in the highest quartile (P < .001). CONCLUSIONS AND RELEVANCE Hospitals with higher quality scores had higher VTE prophylaxis rates but worse risk-adjusted VTE rates. Increased hospital VTE event rates were associated with increasing hospital VTE imaging use rates. Surveillance bias limits the usefulness of the VTE quality measure for hospitals working to improve quality and patients seeking to identify a high-quality hospital.

Prehospital intravenous fluid administration is associated with higher mortality in trauma patients: A national trauma data bank analysis

OBJECTIVE Prehospital intravenous (IV) fluid administration is common in trauma patients, although little evidence supports this practice. We hypothesized that trauma patients who received prehospital IV fluids have higher mortality than trauma patients who did not receive IV fluids in the prehospital setting. METHODS We performed a retrospective cohort study of patients from the National Trauma Data Bank. Multiple logistic regression was used with mortality as the primary outcome measure. We compared patients with versus without prehospital IV fluid administration, using patient demographics, mechanism, physiologic and anatomic injury severity, and other prehospital procedures as covariates. Subset analysis was performed based on mechanism (blunt/penetrating), hypotension, immediate surgery, severe head injury, and injury severity score. RESULTS A total of 776,734 patients were studied. Approximately half (49.3%) received prehospital IV. Overall mortality was 4.6%. Unadjusted mortality was significantly higher in patients receiving prehospital IV fluids (4.8% vs. 4.5%, P < 0.001). Multivariable analysis demonstrated that patients receiving IV fluids were significantly more likely to die (odds ratio [OR] 1.11, 95% confidence interval [CI] 1.05–1.17). The association was identified in nearly all subsets of trauma patients. It is especially marked in patients with penetrating mechanism (OR 1.25, 95% CI 1.08–1.45), hypotension (OR 1.44, 95% CI1.29–1.59), severe head injury (OR 1.34, 95% CI 1.17–1.54), and patients undergoing immediate surgery (OR 1.35, 95% CI 1.22–1.50). CONCLUSIONS The harm associated with prehospital IV fluid administration is significant for victims of trauma. The routine use of prehospital IV fluid administration for all trauma patients should be discouraged.

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?

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.

Surveillance bias and deep vein thrombosis in the national trauma data bank: the more we look, the more we find.

BACKGROUND Deep vein thrombosis (DVT) has been identified as a marker of quality of care by various governmental and consumer groups. However, the lack of standardized DVT screening systems across trauma centers may introduce surveillance bias in the rates of DVT reported. We hypothesize that trauma centers with higher rates of duplex ultrasound detect more DVTs and subsequently report higher DVT rates to the National Trauma Data Bank. METHODS We queried the National Trauma Data Bank version 6.1 and calculated ultrasound rates and DVT rates per trauma center. We excluded hospitals that did not report performing any ultrasounds or any complications. Simple and multiple linear regressions were used to describe the association between ultrasound and DVT rates among hospitals. RESULTS One hundred forty-seven hospitals (16%) met the inclusion criteria, accounting for 578,252 patients (39% of the total patients in the dataset). When dividing hospitals into quartiles by duplex ultrasound rate, the DVT rate in the highest quartile was 7-fold higher than the average combined DVT rate in the first three quartiles (1.52% vs. 0.22%; p < 0.001). Multivariable analysis suggested that hospitals with an ultrasound rate </=2% had a 1.07% increase in reported DVT rate for every 1% increase in ultrasound rate (95% confidence interval 1.05-1.09; p < 0.001). CONCLUSIONS More aggressive screening procedures may be associated with higher DVT rates. Trauma centers that screen more and report higher DVT rates may be falsely labeled as having decreased quality of care. Using DVT rate alone as an independent quality measure should be reevaluated because of the potential for surveillance bias.

Spine immobilization in penetrating trauma: more harm than good?

BACKGROUND Previous studies have suggested that prehospital spine immobilization provides minimal benefit to penetrating trauma patients but takes valuable time, potentially delaying definitive trauma care. We hypothesized that penetrating trauma patients who are spine immobilized before transport have higher mortality than nonimmobilized patients. METHODS We performed a retrospective analysis of penetrating trauma patients in the National Trauma Data Bank (version 6.2). Multiple logistic regression was used with mortality as the primary outcome measure. We compared patients with versus without prehospital spine immobilization, using patient demographics, mechanism (stab vs. gunshot), physiologic and anatomic injury severity, and other prehospital procedures as covariates. Subset analysis was performed based on Injury Severity Score category, mechanism, and blood pressure. We calculated a number needed to treat and number needed to harm for spine immobilization. RESULTS In total, 45,284 penetrating trauma patients were studied; 4.3% of whom underwent spine immobilization. Overall mortality was 8.1%. Unadjusted mortality was twice as high in spine-immobilized patients (14.7% vs. 7.2%, p < 0.001). The odds ratio of death for spine-immobilized patients was 2.06 (95% CI: 1.35-3.13) compared with nonimmobilized patients. Subset analysis showed consistent trends in all populations. Only 30 (0.01%) patients had incomplete spinal cord injury and underwent operative spine fixation. The number needed to treat with spine immobilization to potentially benefit one patient was 1,032. The number needed to harm with spine immobilization to potentially contribute to one death was 66. CONCLUSIONS Prehospital spine immobilization is associated with higher mortality in penetrating trauma and should not be routinely used in every patient with penetrating trauma.

Practice management guidelines for management of hemothorax and occult pneumothorax.

STATEMENT OF THE PROBLEMThoracic trauma is a notable cause of morbidity and mortality in American trauma centers, where 25% of traumatic deaths are related to injuries sustained within the thoracic cage.1 Chest injuries occur in ∼60% of polytrauma cases; therefore, a rough estimate of the occurrence

Lessons from the Johns Hopkins Multi-Disciplinary Venous Thromboembolism (VTE) Prevention Collaborative

Problem Venous thromboembolism (VTE) is a common cause of potentially preventable mortality, morbidity, and increased medical costs. Risk-appropriate prophylaxis can prevent most VTE events, but only a small fraction of patients at risk receive this treatment. Design Prospective quality improvement programme. Setting Johns Hopkins Hospital, Baltimore, Maryland, USA. Strategies for change A multidisciplinary team established a VTE Prevention Collaborative in 2005. The collaborative applied the four step TRIP (translating research into practice) model to develop and implement a mandatory clinical decision support tool for VTE risk stratification and risk-appropriate VTE prophylaxis for all hospitalised adult patients. Initially, paper based VTE order sets were implemented, which were then converted into 16 specialty-specific, mandatory, computerised, clinical decision support modules. Key measures for improvement VTE risk stratification within 24 hours of hospital admission and provision of risk-appropriate, evidence based VTE prophylaxis. Effects of change The VTE team was able to increase VTE risk assessment and ordering of risk-appropriate prophylaxis with paper based order sets to a limited extent, but achieved higher compliance with a computerised clinical decision support tool and the data feedback which it enabled. Risk-appropriate VTE prophylaxis increased from 26% to 80% for surgical patients and from 25% to 92% for medical patients in 2011. Lessons learnt A computerised clinical decision support tool can increase VTE risk stratification and risk-appropriate VTE prophylaxis among hospitalised adult patients admitted to a large urban academic medical centre. It is important to ensure the tool is part of the clinician’s normal workflow, is mandatory (computerised forcing function), and offers the requisite modules needed for every clinical specialty.