Catherine Wolff

Geographic Access to Acute Stroke Care in the United States

Background and Purpose— Only 3% to 5% of patients with acute ischemic stroke receive intravenous recombinant tissue-type plasminogen activator (r-tPA) and <1% receive endovascular therapy. We describe access of the US population to all facilities that actually provide intravenous r-tPA or endovascular therapy for acute ischemic stroke. Methods— We used US demographic data and intravenous r-tPA and endovascular therapy rates in the 2011 US Medicare Provider and Analysis Review data set. International Classification of Diseases-Ninth Revision codes 433.xx, 434.xx and 436 identified acute ischemic stroke cases. International Classification of Diseases-Ninth Revision code 99.10 defined intravenous r-tPA treatment and International Classification of Diseases-Ninth Revision code 39.74 defined endovascular therapy. We estimated ambulance response times using arc-Geographic Information System’s network analyst and helicopter transport times using validated models. Population access to care was determined by summing the population contained within travel sheds that could reach capable hospitals within 60 and 120 minutes. Results— Of 370 351 acute ischemic stroke primary diagnosis discharges, 14 926 (4%) received intravenous r-tPA and 1889 (0.5%) had endovascular therapy. By ground, 81% of the US population had access to intravenous-capable hospitals within 60 minutes and 56% had access to endovascular-capable hospitals. By air, 97% had access to intravenous-capable hospitals within 60 minutes and 85% had access to endovascular hospitals. Within 120 minutes, 99% of the population had access to both intravenous and endovascular hospitals. Conclusions— More than half of the US population has geographic access to hospitals that actually deliver acute stroke care but treatment rates remain low. These data provide a national perspective on acute stroke care and should inform the planning and optimization of stroke systems in the United States.

Characteristics and outcomes of injured patients presenting by private vehicle in a state trauma system

BACKGROUND Previous studies have demonstrated lower mortality among patients transported to single urban trauma centers by private vehicle (PV) compared with Emergency Medical Services (EMS). We sought to describe the characteristics and outcomes of injured patients transported by PV in a state trauma system compared to patients transported by EMS. METHODS We performed a retrospective cohort study of state trauma registry data for patients admitted to all Pennsylvania trauma centers over 5 years (1/2003 to 12/2007). Our primary exposure of interest was prehospital mode of transport and our primary outcome of interest was in-hospital mortality. Unadjusted analyses were performed as were adjusted analyses controlling for injury severity. Data are presented as percents, odds ratios (ORs), and 95% confidence intervals. RESULTS Of the 91132 patients analyzed, 9.6% were transported to the emergency department by PV and 90.4% by EMS. Overall Injury Severity Score (ISS) was 13.3 ± 11.0 (ISS for EMS 13.7 ± 11.3, PV 9.2 ± 7.1, P < .001), and 6.6% of patients died (EMS 7.1%, PV 1.5%, P < .001). After adjusting for injury severity, patients transported by EMS were more likely to die than PV patients (OR 1.9 [95% CI 1.5-2.4]). This effect persisted in blunt, penetrating, advanced life support, and basic life support subgroups, but not in the severely injured (ISS >15, ISS >25) subgroups. CONCLUSIONS Nearly 10% of injured patients arrive at trauma centers by private vehicle. Transport of injured patients by EMS was associated with higher mortality than PV transport. This may reflect the effects of prehospital time, prehospital interventions, or other confounders.

Disparities in Accessibility of Certified Primary Stroke Centers

Background and Purpose— We examine whether the proportion of the US population with ⩽60 minute access to Primary Stroke Centers (PSCs) varies based on geographic and demographic factors. Methods— Population level access to PSCs within 60 minutes was estimated using validated models of prehospital time accounting for critical prehospital time intervals and existing road networks. We examined the association between geographic factors, demographic factors, and access to care. Multivariable models quantified the association between demographics and PSC access for the entire United States and then stratified by urbanicity. Results— Of the 309 million people in the United States, 65.8% had ⩽60 minute PSC access by ground ambulance (87% major cities, 59% minor cities, 9% suburbs, and 1% rural). PSC access was lower in stroke belt states (44% versus 69%). Non-whites were more likely to have access than whites (77% versus 62%), and Hispanics were more likely to have access than non-Hispanics (78% versus 64%). Demographics were not meaningfully associated with access in major cities or suburbs. In smaller cities, there was less access in areas with lower income, less education, more uninsured, more Medicare and Medicaid eligibles, lower healthcare utilization, and healthcare resources. Conclusions— There are significant geographic disparities in access to PSCs. Access is limited in nonurban areas. Despite the higher burden of cerebrovascular disease in stroke belt states, access to care is lower in these areas. Selecting demographic and healthcare factors is strongly associated with access to care in smaller cities, but not in other areas, including major cities.

Volume-outcome relationship in neurotrauma care

OBJECT A positive correlation between outcomes and the volume of patients seen by a provider has been supported by numerous studies. Volume-outcome relationships (VORs) have been well documented in the setting of both neurosurgery and trauma care and have shaped regionalization policies to optimize patient outcomes. Several authors have also investigated the correlation between patient volume and cost of care, known as the volume-cost relationship (VCR), with mixed results. The purpose of the present study was to investigate VORs and VCRs in the treatment of common intracranial injuries by testing the hypotheses that outcomes suffer at small-volume centers and costs rise at large-volume centers. METHODS The authors performed a cross-sectional cohort study of patients with neurological trauma using the 2006 Nationwide Inpatient Sample, the largest nationally representative all-payer data set. Patients were identified using ICD-9 codes for subdural, subarachnoid, and extradural hemorrhage following injury. Transfers were excluded from the study. In the primary analysis the association between a facilitys neurotrauma patient volume and patient survival was tested. Secondary analyses focused on the relationships between patient volume and discharge status as well as between patient volume and cost. Analyses were performed using logistic regression. RESULTS In-hospital mortality in the overall cohort was 9.9%. In-hospital mortality was 14.9% in the group with the smallest volume of patients, that is, fewer than 6 cases annually. At facilities treating 6-11, 12-23, 24-59, and 60+ patients annually, mortality was 8.0%, 8.3%, 9.5%, and 10.0%, respectively. For these groups there was a significantly reduced risk of in-hospital mortality as compared with the group with fewer than 6 annual patients; the adjusted ORs (and corresponding 95% CIs) were 0.45 (0.29-0.68), 0.56 (0.38-0.81), 0.63 (0.44-0.90), and 0.59 (0.41-0.87), respectively. For these same groups (once again using < 6 cases/year as the reference), there were no statistically significant differences in either estimated actual cost or duration of hospital stay. CONCLUSIONS A VOR exists in the treatment of neurotrauma, and a meaningful threshold for significantly improved mortality is 6 cases per year. Emergency and interfacility transport policies based on this threshold might improve national outcomes. Cost of care does not differ significantly with patient volume.

Optimization modeling to maximize population access to comprehensive stroke centers

Objective: The location of comprehensive stroke centers (CSCs) is critical to ensuring rapid access to acute stroke therapies; we conducted a population-level virtual trial simulating change in access to CSCs using optimization modeling to selectively convert primary stroke centers (PSCs) to CSCs. Methods: Up to 20 certified PSCs per state were selected for conversion to maximize the population with 60-minute CSC access by ground and air. Access was compared across states based on region and the presence of state-level emergency medical service policies preferentially routing patients to stroke centers. Results: In 2010, there were 811 Joint Commission PSCs and 0 CSCs in the United States. Of the US population, 65.8% had 60-minute ground access to PSCs. After adding up to 20 optimally located CSCs per state, 63.1% of the US population had 60-minute ground access and 86.0% had 60-minute ground/air access to a CSC. Across states, median CSC access was 55.7% by ground (interquartile range 35.7%–71.5%) and 85.3% by ground/air (interquartile range 59.8%–92.1%). Ground access was lower in Stroke Belt states compared with non–Stroke Belt states (32.0% vs 58.6%, p = 0.02) and lower in states without emergency medical service routing policies (52.7% vs 68.3%, p = 0.04). Conclusion: Optimal system simulation can be used to develop efficient care systems that maximize accessibility. Under optimal conditions, a large proportion of the US population will be unable to access a CSC within 60 minutes.

Unintentional firearm death across the urban-rural landscape in the United States.

BACKGROUND Unintentional injuries are one of the leading causes of death in the United States. Many of these injuries are preventable, and unintentional firearm injuries, in particular, may be responsive to prevention efforts. We investigated the relationship between unintentional firearm death and urbanicity among adults. METHODS This study was a retrospective analysis of national death certificate data. Unintentional adult firearm deaths in the United States from 1999 to 2006 were identified using the Multiple Cause of Death Data files from the National Center for Health Statistics. Decedents were assigned to a county of death and classified along an urban-rural continuum defined by population density and proximity to metropolitan areas. Total unintentional firearm death rates by county were analyzed in adjusted analyses using negative binomial regression. RESULTS A total of 4,595 unintentional firearm injury deaths of adults occurred in the United States during the study period (a mean of 574.4 per year). Adjusted rates of unintentional firearm death showed increases from urban to rural counties. Americans in the most rural counties were significantly more likely to die of unintentional firearm deaths than those in the most urban counties (relative rate, 2.16; 95% confidence interval, 1.44–3.21, p = 0.002). CONCLUSION Rates of unintentional firearm death are significantly higher in rural counties than in urban counties. Prevention strategies should be tailored to account for both geographic location and manner of firearm injury. LEVEL OF EVIDENCE Epidemiologic study, level III.

Reassessing the Stroke Belt: Using Small Area Spatial Statistics to Identify Clusters of High Stroke Mortality in the United States.

Background and Purpose— The stroke belt is described as an 8-state region with high stroke mortality across the southeastern United States. Using spatial statistics, we identified clusters of high stroke mortality (hot spots) and adjacent areas of low stroke mortality (cool spots) for US counties and evaluated for regional differences in county-level risk factors. Methods— A cross-sectional study of stroke mortality was conducted using Multiple Cause of Death data (Centers for Disease Control and Prevention) to compute age-adjusted adult stroke mortality rates for US counties. Local indicators of spatial association statistics were used for hot-spot mapping. County-level variables were compared between hot and cool spots. Results— Between 2008 and 2010, there were 393 121 stroke-related deaths. Median age-adjusted adult stroke mortality was 61.7 per 100 000 persons (interquartile range=51.4–74.7). We identified 705 hot-spot counties (22.4%) and 234 cool-spot counties (7.5%); 44.5% of hot-spot counties were located outside of the stroke belt. Hot spots had greater proportions of black residents, higher rates of unemployment, chronic disease, and healthcare utilization, and lower median income and educational attainment. Conclusions— Clusters of high stroke mortality exist beyond the 8-state stroke belt, and variation exists within the stroke belt. Reconsideration of the stroke belt definition and increased attention to local determinants of health underlying small area regional variability could inform targeted healthcare interventions.

Disparities in access to trauma care in the United States: A population-based analysis

BACKGROUND Injury is a major contributor to morbidity and mortality in the United States. Accordingly, expanding access to trauma care is a Healthy People priority. The extent to which disparities in access to trauma care exist in the US is unknown. Our objective was to describe geographic, demographic, and socioeconomic disparities in access to trauma care in the United States. METHODS Cross-sectional study of the US population in 2010 using small units of geographic analysis and validated estimates of population access to a Level I or II trauma center within 60minutes via ambulance or helicopter. We examined the association between geographic, demographic, and socioeconomic factors and trauma center access, with subgroup analyses of urban-rural disparities. RESULTS Of the 309 million people in the US in 2010, 29.7 million lacked access to trauma care. Across the country, areas with higher income were significantly more likely to have access (OR 1.30, 95% CI 1.12-1.50), as were major cities (OR 2.13, 95% CI 1.25-3.62) and suburbs (OR 1.27, 95% CI 1.02-1.57). Areas with higher rates of uninsured (OR 0.09, 95% CI 0.07-0.11) and Medicaid or Medicare eligible patients (OR 0.69, 95% CI 0.59-0.82) were less likely to have access. Areas with higher proportions of blacks and non-whites were more likely to have access (OR 1.37, 95% CI 1.19-1.58), as were areas with higher proportions of Hispanics and foreign-born persons (OR 1.51, 95% CI 1.13-2.01). Overall, rurality was associated with significantly lower access to trauma care (OR 0.20, 95% CI 0.18-0.23). CONCLUSION While the majority of the United States has access to trauma care within an hour, almost 30 million US residents do not. Significant disparities in access were evident for vulnerable populations defined by insurance status, income, and rurality.

The effects of telemedicine on racial and ethnic disparities in access to acute stroke care

Racial and ethnic disparities have been previously reported in acute stroke care. We sought to determine the effect of telemedicine (TM) on access to acute stroke care for racial and ethnic minorities in the state of Texas. Data were collected from the US Census Bureau, The Joint Commission and the American Hospital Association. Access for racial and ethnic minorities was determined by summing the population that could reach a primary stroke centre (PSC) or telemedicine spoke within specified time intervals using validated models. TM extended access to stroke expertise by 1.5 million residents. The odds of providing 60-minute access via TM were similar in Blacks and Whites (prevalence odds ratios (POR) 1.000, 95% CI 1.000–1.000), even after adjustment for urbanization (POR 1.000, 95% CI 1.000–1.001). The odds of providing access via TM were also similar for Hispanics and non-Hispanics (POR 1.000, 95% CI 1.000–1.000), even after adjustment for urbanization (POR 1.000, 95% CI 1.000–1.000). We found that telemedicine increased access to acute stroke care for 1.5 million Texans. While racial and ethnic disparities exist in other components of stroke care, we did not find evidence of disparities in access to the acute stroke expertise afforded by telemedicine.

Impact of telemedicine on access to acute stroke care in the state of Texas

To examine the impact of telemedicine (TM) on access to acute stroke care and expertise in the state of Texas.