Opioid and other drug use and drug-related mortality as indicators of Hepatitis C and Human Immunodeficiency Virus in Oklahoma.

OBJECTIVES: Outbreaks of injection drug use (IDU)-associated infections have become major public health concerns in the era of the opioid epidemic. This study aimed to (1) identify county-level characteristics associated with acute HCV infection and newly diagnosed IDU-associated HIV in Oklahoma and (2) develop a vulnerability index using these metrics. METHODS: This study employs a county-level ecological design to examine those diagnosed with acute or chronic HCV or newly diagnosed IDU-associated HIV. Poisson regression was used to estimate the association between indicators and the number of new infections in each county. Primary outcomes were acute HCV and newly diagnosed IDU-associated HIV. A sensitivity analysis included all HCV (acute and chronic) cases. Three models were run using variations of these outcomes. Stepwise backward Poisson regression predicted new infection rates and 95% confidence intervals for each county from the final multivariable model, which served as the metric for vulnerability scores. RESULTS: Predictors for HIV-IDU cases and acute HCV cases differed. The percentage of the county population aged 18-24 years with less than a high school education and population density were predictive of new HIV-IDU cases, whereas the percentage of the population that was male, white, Pacific Islander, two or more races, and people aged 18-24 years with less than a high school education were predictors of acute HCV infection. Counties with the highest predicted rates of HIV-IDU tended to be located in central Oklahoma and have higher population density than the counties with the highest predicted rates of acute HCV infection. CONCLUSIONS: There is high variability in county-level factors predictive of new IDU-associated HIV infection and acute HCV infection, suggesting that different public health interventions need to be tailored to these two case populations.

Factors impacting medication adherence in a birth cohort at higher risk for Hepatitis C infection.

Due to the high prevalence of Hepatitis C virus (HCV) infection among individuals born between 1945 and 1965, in 2012 the Centers for Disease Control and Prevention began recommending HCV screening for this birth cohort. As adherence to HCV treatment is essential for sustained virologic response, identifying factors influencing medication adherence is important. The validated Adherence to Refills and Medications Scale (ARMS) is used to study recent medication adherence in those with chronic disease. This cross-sectional pilot study assesses factors associated with reduced adherence, indicated by higher ARMS scores, among individuals in this birth cohort. To elucidate factors associated with medication adherence, measured by the ARMS score, among a birth cohort at higher risk for HCV to guide future treatment and improve adherence. Patients born between 1945 and 1965, accessing care at an academic family medicine clinic, were recruited between April and June 2019. Demographics, prior HCV diagnosis, HCV risk factors (prior imprisonment, tattoos, and intravenous drug use), depression assessment (Patient Health Questionnaire-9), adverse childhood experiences (ACEs), and ARMS scores were collected. Mean ARMS scores were compared using t tests and analysis of variance (α = 0.05), while multiple variable models were performed using linear regression. Women comprised 58% of participants (n = 76), 52% reported depression and 37% 4 or more ACEs. The mean ARMS score was 16.3 (SD = 3.43) and 10% reported prior diagnosis of HCV. In the final multiple variable model, ARMS scores were 2.3 points higher in those with mild depression (95% CI: 0.63, 4.04), 2.0 in those with at least 4 ACEs (95% CI: 0.55, 3.49), and 1.8 in those with tattoos (95% CI: 0.30, 3.28). ACEs and food insecurity were identified as confounding variables in those with moderate to severe depression. This study found medication adherence was related to depression, ACEs, tattoos, and food insecurity among patients in this birth cohort at higher risk for HCV.

Evaluating the Accuracy of the Annual Statewide Kindergarten Vaccination Survey Submitted to Public Health Authorities by School Systems, Oklahoma, 2018.

Recent trends in vaccine hesitancy have brought to light the importance of using accurate school vaccination data. This study evaluated the accuracy of a pilot statewide kindergarten vaccination survey in Oklahoma. School vaccination and exemption data were collected from November 2017 to April 2018 via the Research Electronic Data Capture system. A multivariable linear regression model was used to evaluate the relationship between students who are up to date for all vaccines comparing school reported and Oklahoma State Department of Health-validated data. Adjusted vaccination data were overestimated by 1.0% among public schools and 3.3% among private schools. These results were validated by a random audit of participating schools finding the school-reported vaccination data to be overestimated by 0.6% compared to true student immunization records on file. Our analysis indicates that school-reported vaccination data are sufficiently valid. Immunization record audits provide confidence in available data, which drives evidence-based decision-making.

Cancer-associated venous thromboembolism: Incidence and features in a racially diverse population.

BACKGROUND: Data on the population-based incidence of cancer-associated venous thromboembolism (VTE) from racially diverse populations are limited. OBJECTIVE: To evaluate the incidence and burden of cancer-associated VTE, including demographic and racial subgroups in the general population of Oklahoma County-which closely mirrors the United States. DESIGN: A population-based prospective study. SETTING: We conducted surveillance of VTE at tertiary care facilities and outpatient clinics in Oklahoma County, Oklahoma, from 2012-2014. Surveillance included reviewing all imaging reports used to diagnose VTE and identifying VTE events from hospital discharge data and death certificates. Cancer status was determined by linkage to the Oklahoma Central Cancer Registry. MEASUREMENTS: We used Poisson regression to calculate crude and age-adjusted incidence rates of cancer-associated VTE per 100 000 general population per year, with 95% confidence intervals (95% CI). RESULTS: The age-adjusted incidence (95% CI) of cancer-associated VTE among adults age ≥ 18 was 70.0 (65.1-75.3). The age-adjusted incidence rates (95% CI) were 85.9 (72.7-101.6) for non-Hispanic Blacks, 79.5 (13.2-86.5) for non-Hispanic Whites, 18.8 (8.9-39.4) for Native Americans, 15.6 (7.0-34.8) for Asian/Pacific Islanders, and 15.2 (9.2-25.1) for Hispanics. Recurrent VTE up to 2 years after the initial diagnosis occurred in 38 of 304 patients (12.5%) with active cancer and in 34 of 424 patients (8.0%) with a history of cancer > 6 months previously. CONCLUSION: Age-adjusted incidence rates of cancer-associated VTE vary substantially by race and ethnicity. The relatively high incidence rates of first VTE and of recurrence warrant further assessment of strategies to prevent VTE among cancer patients.

Cost-Benefit Analysis of Allowing Additional Time in Cleaning Hospital Contact Precautions Rooms.

Increasing cleaning time may reduce hospital-acquired transmission of Clostridioides difficile, methicillin-resistant Staphylococcus aureus (MRSA), and vancomycin-resistant enterococcus (VRE). We constructed a cost-benefit model to estimate the impact of implementing an enhanced cleaning protocol, allowing hospital housekeepers an additional 15 minutes to terminally clean contact precautions rooms. The enhanced cleaning protocol saved the hospital $758 per terminally-cleaned room when accounting for only C. difficile. Scaling up to a hospital with 100 cases of C. difficile/year, and the US annual C. difficile incidence, cost savings were $75,832/year and $169.8 million/year, respectively. These results may inform infection control strategic decision-making and resource allocation.

Incidence of Venous Thromboembolism in a Racially Diverse Population of Oklahoma County, Oklahoma.

BACKGROUND: Contemporary incidence data for venous thromboembolism (VTE) from racially diverse populations are limited. The racial distribution of Oklahoma County closely mirrors that of the United States. OBJECTIVE: To evaluate VTE incidence and mortality, including demographic and racial subgroups. DESIGN: Population-based prospective study. SETTING: We conducted VTE surveillance at all relevant tertiary care facilities and outpatient clinics in Oklahoma County, Oklahoma during 2012 to 2014, using both active and passive methods. Active surveillance involved reviewing all imaging reports used to diagnose VTE. Passive surveillance entailed identifying VTE events from hospital discharge data and death certificate records. MEASUREMENTS: We used Poisson regression to calculate crude, age-stratified, and age-adjusted incidence and mortality rates per 1,000 population per year and 95% confidence intervals (CIs). RESULTS: The incidence rate of all VTE was 3.02 (2.92-3.12) for those age ≥18 years and 0.05 (0.04-0.08) for those <18 years. The age-adjusted incidence rates of all VTE, deep vein thrombosis, and pulmonary embolism were 2.47 (95% CI: 2.39-2.55), 1.47 (1.41-1.54), and 0.99 (0.93-1.04), respectively. The age-adjusted VTE incidence and the 30-day mortality rates, respectively, were 0.63 and 0.121 for Asians/Pacific Islanders, 3.25 and 0.355 for blacks, 0.67 and 0.111 for Hispanics, 1.25 and 0.195 for Native Americans, and 2.71 and 0.396 for whites. CONCLUSION: The age-adjusted VTE incidence and mortality rates vary substantially by race. The incidence of three per 1,000 adults per year indicates an important disease burden, and is informative of the burden in the U.S.

Age-sex specific pulmonary embolism-related mortality in the USA and Canada, 2000-18: an analysis of the WHO Mortality Database and of the CDC Multiple Cause of Death database.

BACKGROUND: Pulmonary embolism (PE)-related mortality is decreasing in Europe. However, time trends in the USA and Canada remain uncertain because the most recent analyses of PE-related mortality were published in the early 2000s. METHODS: For this retrospective epidemiological study, we accessed medically certified vital registration data from the WHO Mortality Database (USA and Canada, 2000-17) and the Multiple Cause of Death database produced by the Division of Vital Statistics of the US Centers for Disease Control and Prevention (CDC; US, 2000-18). We investigated contemporary time trends in PE-related mortality in the USA and Canada and the prevalence of conditions contributing to PE-related mortality reported on the death certificates. We also estimated PE-related mortality by age group and sex. A subgroup analysis by race was performed for the USA. FINDINGS: In the USA, the age-standardised annual mortality rate (PE as the underlying cause) decreased from 6·0 deaths per 100 000 population (95% CI 5·9-6·1) in 2000 to 4·4 deaths per 100 000 population (4·3-4·5) in 2006. Thereafter, it continued to decrease to 4·1 deaths per 100 000 population (4·0-4·2) in women in 2017 and plateaued at 4·5 deaths per 100 000 population (4·4-4·7) in men in 2017. Among adults aged 25-64 years, it increased after 2006. The median age at death from PE decreased from 73 years to 68 years (2000-18). The prevalence of cancer, respiratory diseases, and infections as a contributing cause of PE-related death increased in all age categories from 2000 to 2018. The annual age-standardised PE-related mortality was consistently higher by up to 50% in Black individuals than in White individuals; these rates were approximately 50% higher in White individuals than in those of other races. In Canada, the annual age-standardised mortality rate from PE as the underlying cause of death decreased from 4·7 deaths per 100 000 population (4·4-5·0) in 2000 to 2·6 deaths per 100 000 population (2·4-2·8) in 2017; this decline slowed after 2006 across age groups and sexes. INTERPRETATION: After 2006, the initially decreasing PE-related mortality rates in North America progressively reached a plateau in Canada, while a rebound increase was observed among young and middle-aged adults in the USA. These findings parallel recent upward trends in mortality from other cardiovascular diseases and might reflect increasing inequalities in the exposure to risk factors and access to health care. FUNDING: None.

COVID-19 Mortality Among American Indian and Alaska Native Persons - 14 States, January-June 2020.

American Indian/Alaska Native (AI/AN) persons experienced disproportionate mortality during the 2009 influenza A(H1N1) pandemic (1,2). Concerns of a similar trend during the coronavirus disease 2019 (COVID-19) pandemic led to the formation of a workgroup* to assess the prevalence of COVID-19 deaths in the AI/AN population. As of December 2, 2020, CDC has reported 2,689 COVID-19-associated deaths among non-Hispanic AI/AN persons in the United States.† A recent analysis found that the cumulative incidence of laboratory-confirmed COVID-19 cases among AI/AN persons was 3.5 times that among White persons (3). Among 14 participating states, the age-adjusted AI/AN COVID-19 mortality rate (55.8 deaths per 100,000; 95% confidence interval [CI] = 52.5-59.3) was 1.8 (95% CI = 1.7-2.0) times that among White persons (30.3 deaths per 100,000; 95% CI = 29.9-30.7). Although COVID-19 mortality rates increased with age among both AI/AN and White persons, the disparity was largest among those aged 20-49 years. Among persons aged 20-29 years, 30-39 years, and 40-49 years, the COVID-19 mortality rates among AI/AN were 10.5, 11.6, and 8.2 times, respectively, those among White persons. Evidence that AI/AN communities might be at increased risk for COVID-19 illness and death demonstrates the importance of documenting and understanding the reasons for these disparities while developing collaborative approaches with federal, state, municipal, and tribal agencies to minimize the impact of COVID-19 on AI/AN communities. Together, public health partners can plan for medical countermeasures and prevention activities for AI/AN communities.

Tabletop exercise to prepare institutions of higher education for an outbreak of COVID-19.

Complete Table Top Exercise Manual.

Tabletop exercise to prepare institutions of higher education for an outbreak of COVID-19.

Preparing for public health emergencies is an ongoing process and involves a variety of approaches and tools. Tabletop exercises are one of the tools designed to simulate the emergence of a public health emergency and address some or all of the phases of emergency management: mitigation, preparedness, response, and recovery.1 They typically are designed to include participation of stakeholders from diverse and complementary backgrounds, including command, operations, logistics, planning, and finance.2 Effective tabletop exercises provide a plausible scenario that require cooperation and communication from these functional areas. Tabletops also require forward thinking and planning in a variety of scenarios. When a public health emergency occurs, decision makers may be overwhelmed with decisions that need their immediate attention. Tabletop exercises can provide a framework to help decision makers anticipate future challenges, which may provide the mental model encompassing knowledge and insights that inform both current and future decisions.

Is There Less Opioid Abuse in States Where Marijuana Has Been Decriminalized, Either for Medicinal or Recreational Use? A Clin-IQ.

Opioid use, abuse, and associated mortality have reached an epidemic level. In some states, cannabis is being used to treat chronic pain. To examine the hypothesis that medical marijuana legislation may reduce adverse opioid-related outcomes if patients substitute cannabis for opioids for pain management, we conducted a clinical inquiry (Clin-IQ). We searched Ovid MEDLINE, Ovid MEDLINE In-Process, and Embase for studies using the search terms marijuana, cannabis, legal, marijuana smoking, medical marijuana, opioid-related disorders, cannabis use, medical cannabis, legal aspect, and opiate addiction. We included population-based articles published from January 1, 2012, through December 5, 2018, that assessed the relationship between marijuana use and decriminalization and the aforementioned opioid-related outcomes. Ten peer-reviewed studies met the inclusion criteria; 3 cross-sectional studies, 6 ecologic studies (ie, using aggregate data), and 1 retrospective cohort study. Eight studies reported associations between policies decriminalizing marijuana and reduced prescription opioid use, 1 study was inconclusive, and the retrospective cohort study reported an increase in adverse opioid-related outcomes. These results should be interpreted with caution given limitations associated with the studies' design. Results demonstrating association between marijuana decriminalization and opioid-related outcomes are mixed. Longitudinal studies are needed, and further analysis of this policy should continue to be tracked.

Managing emerging transnational public health security threats: lessons learned from the 2014 West African Ebola outbreak.

BACKGROUND: Pandemics pose significant security/stability risks to nations with fragile infrastructures. We evaluated characteristics of the 2014 West African Ebola outbreak to elucidate lessons learned for managing transnational public health security threats. METHODS: We used publically available data to compare demographic and outbreak-specific data for Guinea, Sierra Leone, and Liberia, including key indicator data by the World Health Organization. Pearson correlation statistics were calculated to compare country-level infrastructure characteristics with outbreak size and duration. RESULTS: Hospital bed density was inversely correlated with longer EVD outbreak duration (r = - 0.99). Country-specific funding amount allocations were more likely associated with number of incident cases than the population at-risk or infrastructure needs. Key indicators demonstrating challenges for Guinea included: number of unsafe burials, percent of EVD-positive samples, and days between symptom onset and case hospitalization. Sierra Leone's primary key indicator was the number of districts with ≥1 security incident. Liberia controlled their outbreak before much of the key-indicator data were collected. CONCLUSION: Many of the country-level factors, particularly the WHO key indicators were associated with controlling the epidemic. The infrastructure of countries affected by communicable diseases should be assessed by international political and public health leaders.

Global public awareness about atrial fibrillation.

BACKGROUND: Atrial fibrillation (AF) is an important cause of ischemic stroke that often remains undetected until stroke occurs. Awareness of the risk factors and symptoms is important so that AF can be diagnosed and thromboprophylaxis given. However, the extent of public awareness of AF is uncertain. We assessed public awareness of AF across six continents and compared it with that of other thrombotic and non-thrombotic disorders. METHODS: In collaboration with Ipsos-Reid, we conducted an internet-based, cross-sectional survey between September and October of 2016 in 10 countries: Argentina, Australia, Canada, Germany, Japan, Thailand, the Netherlands, Uganda, United Kingdom, and United States. Participants were selected from survey panels in weighted, age-stratified categories (40-60, 61-74, and ≥75 years). The survey included 11 questions about demographics and assessed awareness about AF, as well as that of other thrombotic and non-thrombotic disorders. Proportions and 95% confidence intervals (CI) were calculated. RESULTS: Of a total of 6312 respondents, overall awareness of AF was 48% (95% CI, 46-50%), which was lower than awareness about other thrombotic and non-thrombotic disorders except for deep vein thrombosis (awareness 43%, 95% CI, 41-45%). Awareness about AF ranged from 25% to 69% across countries, while awareness of the risk factors for AF ranged from 8% to 52%, and awareness that AF leads to stroke ranged from 36% to 46%. Among those reporting awareness of AF, 82% correctly identified palpitations as an AF symptom. CONCLUSIONS: Global public awareness of AF is low. Improving awareness may empower patients to seek timelier stroke preventive care.

Antibiotic prophylaxis for surgical site infections as a risk factor for infection with Clostridium difficile.

OBJECTIVE: We aimed to measure the association between 2013 guideline concordant prophylactic antibiotic use prior to surgery and infection with Clostridium difficile. DESIGN: We conducted a retrospective case-control study by selecting patients who underwent a surgical procedure between January 1, 2012 and December 31, 2013. SETTING: Large urban community hospital. PATIENTS: Cases and controls were patients age 18+ years who underwent an eligible surgery (i.e., colorectal, neurosurgery, vascular/cardiac/thoracic, hysterectomy, abdominal/pelvic and orthopedic surgical procedures) within six months prior to infection diagnosis. Cases were diagnosed with C. difficile infection while controls were not. METHODS: The primary exposure was receiving (vs. not receiving) the recommended prophylactic antibiotic regimen, based on type and duration. Potential confounders included age, sex, length of hospital stay, comorbidities, type of surgery, and prior antibiotic use. Crude and adjusted odds ratios (OR) and 95% confidence intervals (CI) were calculated using logistic regression. RESULTS: We enrolled 68 cases and 220 controls. The adjusted OR among surgical patients between developing C. difficile infection and not receiving the recommended prophylactic antibiotic regimen (usually receiving antimicrobial prophylaxis for more than 24 hours) was 6.7 (95% CI: 2.9-15.5). Independent risk factors for developing C. difficile infection included having severe comorbidities, receiving antibiotics within the previous 6 months, and undergoing orthopedic surgery. CONCLUSIONS: Adherence to the recommended prophylactic antibiotics among surgical patients likely reduces the probability of being case of C. difficile. Antibiotic stewardship should be a priority in strategies to decrease the morbidity, mortality, and costs associated with C. difficile infection.

Impact of World Thrombosis Day campaign.

Thrombosis is an underlying cause of one in four deaths globally. The International Society on Thrombosis and Haemostasis established the inaugural World Thrombosis Day on October 13, 2014. The World Thrombosis Day campaign aims to 1) highlight the disease burden from thrombosis, 2) increase public awareness of the risks, signs, and symptoms of thromboembolic conditions, 3) empower individuals to discuss their thrombosis risk with their healthcare provider, 4) galvanize organizations across the globe, and 5) advocate for "systems of care" to prevent, diagnose, and treat venous thromboembolism and atrial fibrillation. Public health messages include: "know the risks, signs, and symptoms of blood clots," "potentially fatal blood clots in the veins can be prevented," "atrial fibrillation can be diagnosed by a doctor feeling one's pulse," and "effective strategies for stroke prevention in patients with atrial fibrillation are available." To demonstrate the public health impact of the World Thrombosis Day campaign, we measured campaign reach, size and breadth of our partner network, as well as traditional and digital media impressions. The campaign reached an estimated ≥2.3 billion people globally in 2016. As part of the World Thrombosis Day campaign, approximately 8,200 activities were held globally and our partner network expanded to ≥675 partners across 80 countries in 2016. Social media metrics reached 170 million impressions and traditional media reached 1.9 billion impressions. We appreciate and thank our partners for their contributions and encourage others to support this campaign to reduce thrombosis-related morbidity and mortality worldwide.

Impact of a National Cancer Prevention and Treatment Program on the Prevalence of Late-Stage Breast Cancer Diagnoses in Oklahoma.

In 2000, Congress passed the Breast and Cervical Cancer Prevention and Treatment Act (BCCPTA) to provide coverage through Medicaid to women who screened positive for breast and cervical cancer. We aimed to determine if late-stage breast cancer prevalence decreased among Oklahoma women after passage of BCCPTA. Data were obtained from the Oklahoma Central Cancer Registry during 2000-2011. We estimated prevalence proportion ratios (PPR) using modified Poisson regression between the proportion of women with late-stage breast cancer and timing of diagnosis related to BCCPTA. Among uninsured women, the probability of being diagnosed with late-stage cancer after enactment of the BCCPTA was 0.80 (95% CI: 0.67, 0.96) times the probability before enactment. This was significant among uninsured women living in metro counties (PPR: 0.74, 95% CI: 0.61, 0.90) but not in non-metro counties (PPR: 1.05, 95% CI: 0.71, 1.56). These findings may be similar to other rural states with large uninsured populations.

Global Burden of Thrombosis: Epidemiologic Aspects.

Thromboembolic conditions were estimated to account for 1 in 4 deaths worldwide in 2010 and are the leading cause of mortality. Thromboembolic conditions are divided into arterial and venous thrombotic conditions. Ischemic heart disease and ischemic stroke comprise the major arterial thromboses and deep-vein thrombosis and pulmonary embolism comprise venous thromboembolism. Atrial fibrillation is a major risk factor for stroke and systemic arterial thromboembolism. Estimates of the global burden of disease were obtained from Global Burden of Disease Project reports, recent systematic reviews, and searching the published literature for recent studies reporting measures of incidence, burden, and disability-adjusted life-years. Estimates per 100 000 of the global incidence rate (IR) for each condition are ischemic heart disease, IR=1518.7; myocardial infarction, IR=139.3; ischemic stroke, IR=114.3; atrial fibrillation, IR=77.5 in males and 59.5 in females; and venous thromboembolism, IR=115 to 269. Mortality rates (MRs) for each condition are ischemic heart disease, MR=105.5; ischemic stroke, MR=42.3; atrial fibrillation, MR=1.7; and venous thromboembolism, MR=9.4 to 32.3. Global public awareness is substantially lower for pulmonary embolism (54%) and deep-vein thrombosis (44%) than heart attack (88%) and stroke (85%). Over time, the incidence and MRs of these conditions have improved in developed countries, but are increasing in developing countries. Public health efforts to measure disease burden and increase awareness of symptoms and risk factors need to improve, particularly in low- and middle-income regions to address this leading cause of morbidity and mortality.

The design and implementation of a new surveillance system for venous thromboembolism using combined active and passive methods.

Estimates of venous thromboembolism (VTE) incidence in the United States are limited by lack of a national surveillance system. We implemented a population-based surveillance system in Oklahoma County, OK, for April 1, 2012 to March 31, 2014, to estimate the incidences of first-time and recurrent VTE events, VTE-related mortality, and the proportion of case patients with provoked versus unprovoked VTE. The Commissioner of Health made VTE a reportable condition and delegated surveillance-related responsibilities to the University of Oklahoma, College of Public Health. The surveillance system included active and passive methods. Active surveillance involved reviewing imaging studies (such as chest computed tomography and compression ultrasounds) from all inpatient and outpatient facilities. Interrater agreement between surveillance officers collecting data was assessed using κ. Passive surveillance used International Classification of Disease, Ninth Revision (ICD-9) codes from hospital discharge data to identify cases. The sensitivity and specificity of various ICD-9-based case definitions will be assessed by comparison with cases identified through active surveillance. As of February 1, 2015, we screened 54,494 (99.5%) of the imaging studies and identified 2,725 case patients, of which 91.6% were from inpatient facilities, and 8.4% were from outpatient facilities. Agreement between surveillance officers was high (κ ≥0.61 for 93.2% of variables). Agreement for the diagnosis of pulmonary embolism and diagnosis of deep vein thrombosis was κ = 0.92 (95% CI 0.74-1.00) and κ = 0.89 (95% CI 0.71-1.00), respectively. This surveillance system will provide data on the accuracy of ICD-9-based case definitions for surveillance of VTE events and help the Centers for Disease Control and Prevention develop a national VTE surveillance system.