Susan Pardee Baker

The injury severity score: a method for describing patients with multiple injuries and evaluating emergency care.

A method for comparing death rates of groups of injured persons was developed, using hospital and medical examiner data for more than two thousand persons. The first step was determination of the extent to which injury severity as rated by the Abbreviated Injury Scale correlates with patient survival. Substantial correlation was demonstrated. Controlling for severity of the primary injury made it possible to measure the effect on mortality of additional injuries. Injuries that in themselves would not normally be life-threatening were shown to have a marked effect on mortality when they occurred in combination with other injuries. An Injury Severity Score was developed that correlates well with survival and provides a numerical description of the overall severity of injury for patients with multiple trauma. Results of this investigation indicate that the Injury Severity Score represents an important step in solving the problem of summarizing injury severity, especially in patients with multiple trauma.

Geographic Variations in Mortality from Motor Vehicle Crashes

Using a new technique to study the mortality associated with motor vehicle crashes, we calculated population-based death rates of occupants of motor vehicles during the period 1979 through 1981 and mapped them according to county for the 48 contiguous states of the United States. Mortality was highest in counties of low population density (r = 0.57; P less than 0.0001) and was also inversely correlated with per capita income (r = 0.23; P less than 0.0001). Death rates varied more than 100-fold; for example, Esmeralda County, Nevada, with 0.2 residents per square mile (2.6 km2), had a death rate of 558 per 100,000 population, as compared with Manhattan, New York, with 64,000 residents per square mile and a death rate of 2.5 per 100,000. Differences in road characteristics, travel speeds, seat-belt use, types of vehicles, and availability of emergency care may have been major contributors to these relations.

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.

Medications and diagnoses in relation to falls in a long-term care facility

The association between falls, drugs, and diagnoses in elderly residents of a long‐term care facility was explored using case‐control methodology. The odds of being a faller rather than a control were significant (P < .01) for those taking antidepressants, sedatives/hypnotics, or vasodilators, and for those with osteoarthritis or depression.

Effects of high school driver education on motor vehicle crashes, violations, and licensure

OBJECTIVE We sought evidence in the research literature to determine if (1) high school-aged persons who enroll in a driver education course have fewer motor vehicle-related crashes or violations, or are more likely to obtain a drivers license, than those who do not enroll in driver education courses, and (2) the availability of high school driver education courses is associated with lower community rates of motor vehicle crashes among young drivers. METHODS To be included, a study must: (1) assess the effects of driver education courses or legislation for high school-aged persons; (2) present non-self-reported data for at least one of the following outcome measures: driver licensure rates, motor vehicle-related violations, or crashes; (3) include some form of no intervention comparison group; (4) adequately control for potentially confounding variables; (5) randomly assign participants to control or treatment groups, if a controlled trial. RESULTS Nine studies met our inclusion criteria. Based on these studies, there is no convincing evidence that high school driver education reduces motor vehicle crash involvement rates for young drivers, either at the individual or community level. In fact, by providing an opportunity for early licensure, there is evidence that these courses are associated with higher crash involvement rates for young drivers. CONCLUSIONS Although few driver education curricula have been carefully evaluated, in the absence of evidence that driver education reduces crash involvement rates for young persons, schools and communities should consider other ways to reduce motor vehicle-related deaths in this population, such as graduated licensing.

Childhood injury deaths: National analysis and geographic variations

Twenty-three causes of injury mortality in children ages 0-14 in the United States were analyzed by age, race, sex, and state of residence for the years 1980-85. Motor vehicles caused 37 per cent of all injury-related deaths and were the leading cause of injury mortality in every group except children younger than one year, for whom homicide was the leading cause. Male death rates were at least four times female rates for suicide, unintentional firearm injury, and injuries related to farm machinery or motorcycles. The drowning rate among Whites was almost twice that of Blacks for ages 1-4, but in the 10-14 year age group the drowning rate for Blacks was over three times that of Whites. In general, the highest injury death rates were in the mountain states and the south. Between 1980 and 1985, the suicide rate in the 10-14 year age group more than doubled.

Graduated Driver Licensing Programs and Fatal Crashes of 16-Year-Old Drivers: A National Evaluation

CONTEXT. Implementation of graduated driver licensing programs is associated with reductions in crash rates of young drivers, but graduated driver licensing programs vary in their components. The impact of programs with different components is unknown. OBJECTIVE. The purpose of this work was to determine which graduated driver licensing programs are associated with the greatest reductions in fatal motor vehicle crashes involving 16-year-old drivers. METHODS. We conducted a retrospective study of all 16-year-old drivers involved in fatal crashes in the United States from 1994 through 2004 using data from the Fatality Analysis Reporting System and the US Census Bureau. We measured incidence rate ratios of fatal motor vehicle crashes involving 16-year-old drivers according to graduated driver licensing programs, adjusted for state and year. RESULTS. Compared with state quarters with no graduated driver licensing program components, reductions of 16% to 21% in fatal crash involvement rates of 16-year-old drivers occurred with programs that included ≥3-month mandatory waiting period, nighttime driving restriction, and either ≥30 hours of supervised driving or passenger restriction. Reductions of 18% to 21% occurred in state quarters with programs that included ≥5 of the 7 components examined. Drivers aged 20 to 24 or 25 to 29 years did not experience significant reductions. CONCLUSION. Comprehensive graduated driver licensing programs are associated with reductions of ∼20% in 16-year-old drivers’ fatal crash involvement rates. The greatest benefit seems to be associated with programs that include age requirements and ≥3 months of waiting before the intermediate stage, nighttime driving restriction, and either ≥30 hours of supervised driving or passenger restriction.

Alcohol and injury severity: reappraisal of the continuing controversy

It is well recognized that alcohol increases the risk of injury. It is controversial, however, whether alcohol also has an effect on the degree and outcome of injury after controlling for the severity of impact. This review examines the evidence from experimental studies in animals regarding the potentiating effects of alcohol on trauma, and the methodologic issues that may have contributed to the contradictory findings of clinical and epidemiologic studies. Most experimental studies indicate that alcohol can adversely affect the degree and outcome of injury. In controlled laboratory conditions, alcohol is found to reduce cardiac output, to increase the susceptibility to hemorrhagic shock, and to increase the pulmonary vascular resistance after standardized experimental injuries. However, it is difficult to extrapolate these findings to humans, partly because the interactive effects of chronic and acute alcohol use on trauma are rarely considered in experimental studies. The conflicting results in studies involving trauma patients are due in part to the differences in study design, particularly selection of study populations, and in measuring and controlling for kinetic forces on the body. Studies indicating that alcohol is associated with an increased risk of serious or fatal injury are usually based on data from emergency departments or police departments. The alcohol-injury severity relationship reported in these studies is attributable to a great extent to the effects of correlates of alcohol, such as speeding and not wearing seat belts, rather than the biological effects of alcohol. Studies indicating that alcohol is not associated with the degree and outcomes of injury are mostly those involving patients who were admitted to hospitals or trauma centers. Methodologic issues concerning the alcohol-injury severity controversy, including conceptual models and future research needs, are discussed.

Sports and physical training injury hospitalizations in the army.

INTRODUCTION Injuries are the leading health problem in the military services. Sports and physical training activities are an area in which a substantial number of injuries can occur. Although athletic injuries are not often investigated in military populations, the Armed Forces database provides a unique opportunity to investigate sports injuries. METHODS An Army database of all hospital admissions for active duty Army personnel in the 1989-1994 period was used to study injuries resulting from sports and Army physical training. RESULTS For the 6-year time period reviewed, there were 13,861 hospital admissions for injuries resulting from sports or Army physical training: 94% (13,020) of these admissions were men and 6% (841) were women. The rates of sports injuries were 38 and 18 per 10,000 person-years for men and women, respectively. Sports injuries accounted for an average of 29,435 lost duty days each year: Men lost an average of 13 days per injury and women lost an average of 11 days per injury. Acute musculoskeletal injuries in the categories of fractures, sprains/strains, and dislocations accounted for 82% of all injuries. The knee was the most often injured body area in both genders, with the anterior cruciate ligament (ACL) identified as the most frequently injured body part overall. The top seven injuries were virtually identical for men and women, with only slight variations in order. Although the rates of all hospitalized sports injuries were higher for men than women, women had a higher proportion of ACL injuries from basketball and softball, ankle fractures from softball and head injuries from basketball. For men, football and basketball contributed to the highest rates of injuries. The highest injury rates for women were from Army physical training and basketball. For both men and women, Army physical training was the leading cause of lumbosacral strains. CONCLUSIONS Sports and Army physical training injuries account for a significant amount of lost duty time and impact military readiness.

Are female drivers safer? An application of the decomposition method.

Using the decomposition method and national data for the year 1990, we examined gender and age differences in involvement rates in fatal motor vehicle crashes. The fatal crash involvement rate per driver is expressed as a multiplicative function of the crash fatality rate (defined as the proportion of fatal crashes involved among all crashes involved), crash incidence density (that is, number of crashes per million person-miles), and exposure prevalence (that is, annual average miles driven per driver). The fatal crash involvement rate per 10,000 drivers for men was three times that for women (5.3 vs 1.7) and was highest among teenagers. Of the male-female discrepancy in the fatal crash involvement rates, 51% was attributable to the difference between sexes in crash fatality rates, 41% to the difference in exposure prevalence, and 8% to the difference in crash incidence density. Age-related variations in the fatal crash involvement rates resulted primarily from the differences in crash incidence density. The results indicate that, despite-having lower fatal crash involvement rates, female drivers – do not seem to be safer than their male counterparts when exposure is considered. The decomposition method is valuable as both a conceptual framework and an exploratory tool for understanding the contributing factors related to cause-specific injury mortality and the differences in death rates among populations. (Epidemiology 1998;9:379–384)