African American race was associated with an increased risk of complications following venous thromboembolism

Developing Validated Tools to Identify Pulmonary Embolism in Electronic Databases: Rationale and Design of the PE-EHR+ Study

BACKGROUND

 Contemporary pulmonary embolism (PE) research, in many cases, relies on data from electronic health records (EHRs) and administrative databases that use International Classification of Diseases (ICD) codes. Natural language processing (NLP) tools can be used for automated chart review and patient identification. However, there remains uncertainty with the validity of ICD-10 codes or NLP algorithms for patient identification.

METHODS

 The PE-EHR+ study has been designed to validate ICD-10 codes as Principal Discharge Diagnosis, or Secondary Discharge Diagnoses, as well as NLP tools set out in prior studies to identify patients with PE within EHRs. Manual chart review by two independent abstractors by predefined criteria will be the reference standard. Sensitivity, specificity, and positive and negative predictive values will be determined. We will assess the discriminatory function of code subgroups for intermediate- and high-risk PE. In addition, accuracy of NLP algorithms to identify PE from radiology reports will be assessed.

RESULTS

 A total of 1,734 patients from the Mass General Brigham health system have been identified. These include 578 with ICD-10 Principal Discharge Diagnosis codes for PE, 578 with codes in the secondary position, and 578 without PE codes during the index hospitalization. Patients within each group were selected randomly from the entire pool of patients at the Mass General Brigham health system. A smaller subset of patients will also be identified from the Yale-New Haven Health System. Data validation and analyses will be forthcoming.

CONCLUSIONS

 The PE-EHR+ study will help validate efficient tools for identification of patients with PE in EHRs, improving the reliability of efficient observational studies or randomized trials of patients with PE using electronic databases.

Epidemiology and prevention of venous thromboembolism

Venous thromboembolism, that consists of the interrelated conditions deep-vein thrombosis and pulmonary embolism, is an under-appreciated vascular disease. In Western regions, approximately 1 in 12 individuals will be diagnosed with venous thromboembolism in their lifetime. Rates of venous thromboembolism are lower in Asia, but data from other regions are sparse. Numerous risk factors for venous thromboembolism have been identified, which can be classified as acute or subacute triggers (provoking factors that increase the risk of venous thromboembolism) and basal or acquired risk factors (which can be modifiable or static). Approximately 20% of individuals who have a venous thromboembolism event die within 1 year (although often from the provoking condition), and complications are common among survivors. Fortunately, opportunities exist for primordial prevention (prevention of the development of underlying risk factors), primary prevention (management of risk factors among individuals at high risk of the condition) and secondary prevention (prevention of recurrent events) of venous thromboembolism. In this Review, we describe the epidemiology of venous thromboembolism, including the incidence, risk factors, outcomes and opportunities for prevention. Meaningful health disparities exist in both the incidence and outcomes of venous thromboembolism. We also discuss these disparities as well as opportunities to reduce them.

Enoxaparin Thromboprophylaxis in Children Hospitalized for COVID-19: A Phase 2 Trial

BACKGROUND

Evidence regarding the safety and efficacy of anticoagulant thromboprophylaxis among pediatric patients hospitalized for coronavirus disease 2019 (COVID-19) is limited. We sought to evaluate safety, dose-finding, and preliminary efficacy of twice-daily enoxaparin as primary thromboprophylaxis among children hospitalized for symptomatic COVID-19, including primary respiratory infection and multisystem inflammatory syndrome in children (MISC).

METHODS

We performed a phase 2, multicenter, prospective, open-label, single-arm clinical trial of twice-daily enoxaparin (initial dose: 0.5mg/kg per dose; max: 60mg; target anti-Xa activity: 0.20-0.49IU/mL) as primary thromboprophylaxis for children <18 years of age hospitalized for symptomatic COVID-19. Study endpoints included: cumulative incidence of International Society of Thrombosis and Haemostasis-defined clinically relevant bleeding; enoxaparin dose-requirements; and cumulative incidence of venous thromboembolism within 30-days of hospital discharge. Descriptive statistics summarized endpoint estimates that were further evaluated by participant age (±12 years) and clinical presentation.

RESULTS

Forty children were enrolled and 38 met analyses criteria. None experienced clinically relevant bleeding. Median (interquartile range) dose to achieve target anti-Xa levels was 0.5 mg/kg (0.48-0.54). Dose-requirement did not differ by age (0.5 [0.46-0.52] mg/kg for age ≥12 years versus 0.52 [0.49-0.55] mg/kg for age <12 years, P = .51) but was greater for participants with MISC (0.52 [0.5-0.61] mg/kg) as compared with primary COVID-19 (0.48 [0.39-0.51] mg/kg, P = .010). Two children (5.3%) developed central-venous catheter-related venous thromboembolism. No serious adverse events were related to trial intervention.

CONCLUSIONS

Among children hospitalized for COVID-19, thromboprophylaxis with twice-daily enoxaparin appears safe and warrants further investigation to assess efficacy.

Racial differences in venous thromboembolism: A surveillance program in Durham County, North Carolina

Background

Venous thromboembolism (VTE) affects approximately 1-2 individuals per 1000 annually and is associated with an increased risk for pulmonary hypertension, postthrombotic syndrome, and recurrent VTE.

Objective

To determine risk factors, incidence, treatments, and outcomes of VTE through a 2-year surveillance program initiated in Durham County, North Carolina (population approximately 280,000 at time of study).

Patients/Methods

We performed a retrospective analysis of data actively collected from three hospitals in Durham County during the surveillance period.

Results

A total of 987 patients were diagnosed with VTE, for an annual rate of 1.76 per 1000 individuals. Hospital-associated VTE occurred in 167 hospitalized patients (16.9%) and 271 outpatients who were hospitalized within 90 days of diagnosis (27.5%). Annual incidence was 1.98 per 1000 Black individuals compared to 1.25 per 1000 White individuals (p < 0.0001), and Black individuals with VTE were younger than White individuals (p < 0.0001). Common risk factors included active cancer, prolonged immobility, and obesity, and approximately half were still taking anticoagulant therapy 1 year later. A total of 224 patients died by 1 year (28.5% of patients for whom outcomes could be confirmed), and Black patients were more likely to have recurrent VTE than White patients during the first 6 months following initial presentation (9.4% vs. 4.1%, p = 0.01).

Conclusions

Ongoing surveillance provides an effective strategy to identify patients with VTE and monitor treatment and outcomes. We demonstrated that hospital-associated VTE continues to be a major contributor to the burden of VTE and confirmed the higher incidence of VTE in Black compared to White individuals.

Effect of Anticoagulant Therapy for 6 Weeks vs 3 Months on Recurrence and Bleeding Events in Patients Younger Than 21 Years of Age With Provoked Venous Thromboembolism: The Kids-DOTT Randomized Clinical Trial

Importance

Among patients younger than 21 years of age, the optimal duration of anticoagulant therapy for venous thromboembolism is unknown.

Objective

To test the hypothesis that a 6-week duration of anticoagulant therapy for provoked venous thromboembolism is noninferior to a conventional 3-month therapy duration in patients younger than 21 years of age.

Design, Setting, and Participants

Randomized clinical trial involving 417 patients younger than 21 years of age with acute, provoked venous thromboembolism enrolled at 42 centers in 5 countries from 2008-2021. The main exclusions were severe anticoagulant deficiencies or prior venous thromboembolism. Patients without persistent antiphospholipid antibodies and whose thrombi were resolved or not completely occlusive upon repeat imaging at 6 weeks after diagnosis underwent randomization. The final visit for the primary end points occurred in January 2021.

Interventions

Total duration for anticoagulant therapy of 6 weeks (n = 207) vs 3 months (n = 210) for provoked venous thromboembolism.

Main Outcomes and Measures

The primary efficacy and safety end points were centrally adjudicated symptomatic recurrent venous thromboembolism and clinically relevant bleeding events within 1 year blinded to treatment group. The primary analysis was noninferiority in the per-protocol population. The noninferiority boundary incorporated a bivariate trade-off that included an absolute increase of 0% in symptomatic recurrent venous thromboembolism with an absolute risk reduction of 4% in clinically relevant bleeding events (1 of 3 points on the bivariate noninferiority boundary curve).

Results

Among 417 randomized patients, 297 (median age, 8.3 [range, 0.04-20.9] years; 49% female) met criteria for the primary per-protocol population analysis. The Kaplan-Meier estimate for the 1-year cumulative incidence of the primary efficacy outcome was 0.66% (95% CI, 0%-1.95%) in the 6-week anticoagulant therapy group and 0.70% (95% CI, 0%-2.07%) in the 3-month anticoagulant therapy group, and for the primary safety outcome, the incidence was 0.65% (95% CI, 0%-1.91%) and 0.70% (95% CI, 0%-2.06%). Based on absolute risk differences in recurrent venous thromboembolism and clinically relevant bleeding events between groups, noninferiority was demonstrated. Adverse events occurred in 26% of patients in the 6-week anticoagulant therapy group and in 32% of patients in the 3-month anticoagulant therapy group; the most common adverse event was fever (1.9% and 3.4%, respectively).

Conclusions and Relevance

Among patients younger than 21 years of age with provoked venous thromboembolism, anticoagulant therapy for 6 weeks compared with 3 months met noninferiority criteria based on the trade-off between recurrent venous thromboembolism risk and bleeding risk.

Trial Registration

ClinicalTrials.gov Identifier: NCT00687882.

Effectiveness and Safety of Apixaban Versus Warfarin Among Older Patients with Venous Thromboembolism with Different Demographics and Socioeconomic Status

Introduction

Impact of demographics and socioeconomic status (SES) on anticoagulant treatment outcomes among patients with venous thromboembolism (VTE) is not well understood. This study evaluated risks of recurrent VTE, major bleeding (MB), and clinically relevant non-major bleeding (CRNMB) among older patients with VTE initiating apixaban or warfarin stratified by demographics and SES.

Methods

Adult patients (≥ 65 years) who initiated apixaban or warfarin after a VTE event were selected from the US CMS Medicare database (September 2014–December 2017). Stabilized inverse probability treatment weighting (IPTW) was used to balance patient characteristics between treatment cohorts. Patients were stratified by age, gender, race, and SES. For each subgroup, Cox proportional hazard models were used to evaluate if there was a significant interaction (p < 0.10) between treatment and subgroup for recurrent VTE, MB, and CRNMB.

Results

In total, 22,135 apixaban and 45,840 warfarin patients with VTE were included. Post-IPTW, patient characteristics were balanced between treatment cohorts. In older patients, apixaban treatment was associated with significantly lower risks of recurrent VTE (hazard ratio [HR] 0.64; 95% confidence interval [CI] 0.52–0.79), MB (HR 0.65; 95% CI 0.57–0.75), and CRNMB (HR 0.79; 95% CI 0.75–0.85) versus warfarin. When stratified by demographics and SES, higher incidence rates of recurrent VTE, MB, and CRNMB were observed for black vs white patients and patients with lower vs higher SES. Comparison of apixaban with warfarin by different demographic and SES subgroups showed generally consistent results as the overall analysis. For most subgroups, no significant interaction was observed between treatment and subgroup strata for recurrent VTE, MB, and CRNMB.

Conclusion

Among older patients with VTE initiating apixaban or warfarin, higher rates of recurrent VTE and bleeding were observed in black patients and patients with lower SES. Apixaban had a lower risk of recurrent VTE, MB, and CRNMB compared to warfarin. Analyses of demographic and SES subgroups showed consistent findings.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12325-021-01918-0.

Racial and Ethnic Differences in Response to Anticoagulation: A Review of the Literature

INTRODUCTION

Anticoagulants are among the most frequently prescribed medications in the United States. Racial and ethnic disparities in incidence and outcomes of thrombotic disorders are well-documented, but differences in response to anticoagulation are incompletely understood.

OBJECTIVE

The objective of this review is to describe the impact of race and ethnicity on surrogate and clinical end points related to anticoagulation and discuss racial or ethnic considerations for prescribing anticoagulants.

METHODS

A PubMed and MEDLINE search of clinical trials published between 1950 and May 2018 was conducted using search terms related to anticoagulation, specific anticoagulant drugs, race, and ethnicity. References of identified studies were also reviewed. English-language human studies on safety or efficacy of anticoagulants reporting data for different races or ethnicities were eligible for inclusion.

RESULTS

Seventeen relevant studies were identified. The majority of major trials reviewed for inclusion either did not include representative populations or did not report on the racial breakdown of participants. Racial differences in pharmacokinetics, dosing requirements, drug response, and/or safety end points were identified for unfractionated heparin, enoxaparin, argatroban, warfarin, rivaroxaban, and edoxaban.

CONCLUSIONS

Race appears to influence drug concentrations, dosing, or safety for some but not all direct oral anticoagulants. This information should be considered when selecting anticoagulant therapy for nonwhite individuals.

Anticoagulation Management Practices and Outcomes in Elderly Patients with Acute Venous Thromboembolism: A Clinical Research Study

Whether anticoagulation management practices are associated with improved outcomes in elderly patients with acute venous thromboembolism (VTE) is uncertain. Thus, we aimed to examine whether practices recommended by the American College of Chest Physicians guidelines are associated with outcomes in elderly patients with VTE. We studied 991 patients aged ≥65 years with acute VTE in a Swiss prospective multicenter cohort study and assessed the adherence to four management practices: parenteral anticoagulation ≥5 days, INR ≥2.0 for ≥24 hours before stopping parenteral anticoagulation, early start with vitamin K antagonists (VKA) ≤24 hours of VTE diagnosis, and the use of low-molecular-weight heparin (LMWH) or fondaparinux. The outcomes were all-cause mortality, VTE recurrence, and major bleeding at 6 months, and the length of hospital stay (LOS). We used Cox regression and lognormal survival models, adjusting for patient characteristics. Overall, 9% of patients died, 3% had VTE recurrence, and 7% major bleeding. Early start with VKA was associated with a lower risk of major bleeding (adjusted hazard ratio 0.37, 95% CI 0.20–0.71). Early start with VKA (adjusted time ratio [TR] 0.77, 95% CI 0.69–0.86) and use of LMWH/fondaparinux (adjusted TR 0.87, 95% CI 0.78–0.97) were associated with a shorter LOS. An INR ≥2.0 for ≥24 hours before stopping parenteral anticoagulants was associated with a longer LOS (adjusted TR 1.2, 95% CI 1.08–1.33). In elderly patients with VTE, the adherence to recommended anticoagulation management practices showed mixed results. In conclusion, only early start with VKA and use of parenteral LMWH/fondaparinux were associated with better outcomes.

Racial and Ethnic Disparities in Adverse Drug Events: A Systematic Review of the Literature

The 2014 National Action Plan for Adverse Drug Event Prevention has recognized adverse drug events (ADEs) as a national priority in order to facilitate a nationwide reduction in patient harms from these events. Throughout this effort, it will be integral to identify populations that may be at particular risk in order to improve care for these patients. We have undertaken a systematic review to evaluate the evidence regarding racial or ethnic disparities in ADEs with particular emphasis on anticoagulants, diabetes agents, and opioids due to the clinical significance and preventability of ADEs associated with these medication classes. From an initial search yielding 3302 studies, we identified 40 eligible studies. Twenty-seven of these included studies demonstrated the presence of a racial or ethnic disparity. There was no consistent evidence for racial or ethnic disparities in the eight studies of ADEs in general. Asians were most frequently determined to be at higher risk of anticoagulant-related ADEs, and black patients were most frequently determined to be at higher risk for diabetes agents-related ADEs. Whites were most frequently identified as at increased risk for opioid-related ADEs. However, few of these studies were specifically designed to evaluate racial or ethnic disparities, lacking a standardized approach to racial/ethnic categorization as well as control for potential confounders. We suggest the need for targeted interventions to reduce ADEs in populations that may be at increased risk, and we suggest strategies for future research.

The adherence to initial processes of care in elderly patients with acute venous thromboembolism

BACKGROUND

We aimed to assess whether elderly patients with acute venous thromboembolism (VTE) receive recommended initial processes of care and to identify predictors of process adherence.

METHODS

We prospectively studied in- and outpatients aged ≥65 years with acute symptomatic VTE in a multicenter cohort study from nine Swiss university- and non-university hospitals between September 2009 and March 2011. We systematically assessed whether initial processes of care, which are recommended by the 2008 American College of Chest Physicians guidelines, were performed in each patient. We used multivariable logistic models to identify patient factors independently associated with process adherence.

RESULTS

Our cohort comprised 950 patients (mean age 76 years). Of these, 86% (645/750) received parenteral anticoagulation for ≥5 days, 54% (405/750) had oral anticoagulation started on the first treatment day, and 37% (274/750) had an international normalized ratio (INR) ≥2 for ≥24 hours before parenteral anticoagulation was discontinued. Overall, 35% (53/153) of patients with cancer received low-molecular-weight heparin monotherapy and 72% (304/423) of patients with symptomatic deep vein thrombosis were prescribed compression stockings. In multivariate analyses, symptomatic pulmonary embolism, hospital-acquired VTE, and concomitant antiplatelet therapy were associated with a significantly lower anticoagulation-related process adherence.

CONCLUSIONS

Adherence to several recommended processes of care was suboptimal in elderly patients with VTE. Quality of care interventions should particularly focus on processes with low adherence, such as the prescription of continued low-molecular-weight heparin therapy in patients with cancer and the achievement of an INR ≥2 for ≥24 hours before parenteral anticoagulants are stopped.

Racial and regional differences in venous thromboembolism in the United States in 3 cohorts

BACKGROUND

Blacks are thought to have a higher risk of venous thromboembolism (VTE) than whites. However, prior studies are limited to administrative databases that lack specific information on VTE risk factors or have limited geographic scope.

METHODS AND RESULTS

We ascertained VTE from 3 prospective studies: the Atherosclerosis Risk in Communities Study (ARIC), the Cardiovascular Health Study (CHS), and the Reasons for Geographic and Racial Differences in Stroke study (REGARDS). We tested the association of race with VTE using Cox proportional hazard models adjusted for VTE risk factors. Over 438 090 person-years, 916 incident VTE events (302 in blacks) occurred in 51 149 individuals (17 318 blacks) who were followed up. In risk factor-adjusted models, blacks had a higher rate of VTE than whites in the CHS (hazard ratio, 1.81; 95% confidence interval, 1.20-2.73) but not ARIC (hazard ratio, 1.21; 95% confidence interval, 0.96-1.54). In REGARDS, there was a significant region-by-race interaction (P=0.01): Blacks in the Southeast had a significantly higher rate of VTE than blacks in the rest of the United States (hazard ratio, 1.63; 95% confidence interval, 1.08-2.48) that was not seen in whites (hazard ratio, 0.83; 95% confidence interval, 0.61-1.14).

CONCLUSIONS

The association of race with VTE differed in each cohort, which may reflect the different time periods of the studies or different regional rates of VTE. Further studies of environmental and genetic risk factors for VTE are needed to determine which underlie racial and perhaps regional differences in VTE.

Centers for cardiovascular outcomes research: defining a collaborative vision

BACKGROUND

Recognizing the value of outcomes research to understand and bridge translational gaps, to establish evidence in clinical practice and delivery of medicine, and to generate new hypotheses on ongoing questions of treatment and care, the National Heart, Lung, and Blood Institute of the National Institutes of Health established the Centers for Cardiovascular Outcomes Research program in 2010.

METHODS AND RESULTS

The National Heart, Lung, and Blood Institute funded 3 centers and a research coordinating unit. Each center has an independent project focus, including (1) characterizing care transition and predicting clinical events and quality of life for patients discharged after an acute coronary syndrome; (2) identifying center and regional factors associated with better patient outcomes across several cardiovascular conditions and procedures; and (3) examining the impact of healthcare reform in Massachusetts on overall and disparate care and outcomes for several cardiovascular conditions and venous thromboembolism. Cross-program collaborations seek to advance the field methodologically and to develop early-stage investigators committed to careers in outcomes research.

CONCLUSIONS

The Centers for Cardiovascular Outcomes Research program represents a significant investment in cardiovascular outcomes research by the National Heart, Lung, and Blood Institute. The vision of this program is to leverage scientific rigor and cross-program collaboration to advance the science of healthcare delivery and outcomes beyond what any individual unit could achieve alone.

Comparison of characteristics from White- and Black-Americans with venous thromboembolism: a cross-sectional study

When compared with Whites, Black-Americans may have a 40% higher incidence venous thromboembolism (VTE) incidence. However, whether other VTE characteristics and risk factors vary by race is uncertain. To compare demographic and baseline characteristics among White- and Black-Americans with VTE, we used data prospectively collected from consecutive consenting adults enrolled in seven Centers for Disease Control (CDC) Thrombosis and Hemostasis Centers from August 2003 to March 2009. These characteristics were compared among Whites (n = 2002) and Blacks (n = 395) with objectively diagnosed VTE, both overall, and by age and gender. When compared with Whites, Blacks had a significantly higher proportion with pulmonary embolism (PE), including idiopathic PE among Black women, and a significantly higher proportion of Blacks were women. Blacks had a significantly higher mean BMI and a significantly lower proportion with recent surgery, trauma or infection, family history of VTE, and documented thrombophilia (solely from reduced factor V Leiden and prothrombin G20210A prevalence). Conversely, Blacks had a significantly higher proportion with hypertension, diabetes mellitus, chronic renal disease and dialysis, HIV, and sickle cell disease. When compared with White women, Black women had a significantly lower proportion with recent oral contraceptive use or hormone therapy. We conclude that Whites and Blacks differ significantly regarding demographic and baseline characteristics that may be risk factors for VTE. The prevalence of transient VTE risk factors and idiopathic VTE among Blacks appears to be lower and higher, respectively, suggesting that heritability may be important in the etiology of VTE among Black-Americans.

Venous thromboembolism in African-Americans: a literature-based commentary

Among the cardiovascular diseases and after ischemic heart disease and stroke, venous thromboembolism (VTE) is the third leading cause of death in the U.S. (3). Although VTE is seen across most ethnic groups in the U.S. as well as throughout the world, the rate varies. In the U.S., American Indians/Alaskan Natives as well as Asians have been reported to have a significantly lower rate of deep vein thrombosis (DVT) and pulmonary embolism (PE) as compared to blacks and whites. In sharp conrast blacks appear to have much higher rates than whites. Although these rate differences are thought in part by some to be attributable to disparities in diagnosis and care as well as genetics, it nevertheless is important to define as well as to understand the true incidence and impact so that both public health and clinical resources can be maximally utilized. The purpose of this commentary is to review the VTE burden in the U.S. with respect to ethnicity in terms of clinical demographics and genetics with particular emphasis on blacks.

Venous thromboembolism and ethnicity

Venous thromboembolism (VTE) has long been considered a disease that affects predominantly white populations, a misconception resulting from a paucity of epidemiological data from non-Western countries, and the low incidence of hereditary thrombophilia in those of non-Caucasian background. Over the last decade, interest has grown in this area with the emergence of evidence that VTE is as prevalent, if not more so, in the black population and is also common in Asian groups. Much is still to be learned, as our current knowledge of hereditary thrombophilia and acquired risk factors do not fully explain the risk of VTE in non-Caucasian groups. This review summarises the current understanding of ethnic variation in VTE and highlights the need for further research in this area.

Measuring quality of oral anticoagulation care: extending quality measurement to a new field

BACKGROUND

Oral anticoagulation with warfarin is an increasingly common medical intervention. Despite its efficacy, warfarin is difficult to manage, contributing to potential for patient harm. Efforts to measure the quality of oral anticoagulation care have focused disproportionately on the identification of ideal candidates for warfarin therapy, with comparatively little effort in measuring the quality of oral anticoagulation care once therapy has begun. To address this gap in the literature, a MEDLINE search was conducted for all papers relevant to possible quality measures in oral anticoagulation care, including measures of structure, process, and outcomes of care.

LIMITATIONS, CONCERNS, AND CHALLENGES OF QUALITY MEASUREMENT IN ORAL ANTICOAGULATION

Because they do not have intrinsic significance, measures of structure and process should be strongly related to outcomes that matter to merit our interest. Consensus guidelines may provide useful guidance to practicing clinicians but may not represent valid process measures. Outcome measures must be studied with databases that provide sufficient statistical power to reliably demonstrate real differences between providers or sites of care.

CONCLUSION

Oral anticoagulation care, a common and serious condition, is in need of a program of quality measurement. This article suggests a research agenda to begin such a program. Previous research has established the evidence for anticoagulant therapy across a broad spectrum of indications and has helped to achieve consensus on the optimal target intensity for various indications. The next task will be to use this body of evidence to develop valid measures of the structure, process, and outcomes of oral anticoagulation care. Quality indicators provide a framework for quality improvement, two goals of which are to maximize the effectiveness of therapy and to minimize harm.

Weekend versus weekday admission and mortality after acute pulmonary embolism

BACKGROUND

Optimal management of acute pulmonary embolism (PE) requires medical expertise, diagnostic testing, and therapies that may not be available consistently throughout the entire week. We sought to assess whether associations exist between weekday or weekend admission and mortality and length of hospital stay for patients hospitalized with PE.

METHODS AND RESULTS

We evaluated patients discharged with a primary diagnosis of PE from 186 acute care hospitals in Pennsylvania (January 2000 to November 2002). We used random-effect logistic models to study the association between weekend admission and 30-day mortality and used discrete survival models to study the association between weekend admission and time to hospital discharge, adjusting for hospital (region, size, and teaching status) and patient factors (race, insurance, severity of illness, and use of thrombolytic therapy). Among 15 531 patient discharges with PE, 3286 patients (21.2%) had been admitted on a weekend. Patients admitted on weekends had a higher unadjusted 30-day mortality rate (11.1% versus 8.8%) than patients admitted on weekdays, with no difference in length of stay. Patients admitted on weekends had significantly greater adjusted odds of dying (odds ratio 1.17, 95% confidence interval 1.03 to 1.34) than patients admitted on weekdays. The higher mortality among patients hospitalized on weekends was driven by the increased mortality rate among the most severely ill patients.

CONCLUSIONS

Patients with PE who are admitted on weekends have a significantly higher short-term mortality than patients admitted on weekdays. Quality-improvement efforts should aim to ensure a consistent approach to the management of PE 7 days a week.

Hospital volume and patient outcomes in pulmonary embolism

BACKGROUND

In numerous high-risk medical and surgical conditions, a greater volume of patients undergoing treatment in a given setting or facility is associated with better survival. For patients with pulmonary embolism, the relation between the number of patients treated in a hospital (volume) and patient outcome is unknown.

METHODS

We studied discharge records from 186 acute care hospitals in Pennsylvania for a total of 15 531 patients for whom the primary diagnosis was pulmonary embolism. The study outcomes were all-cause mortality in hospital and within 30 days after presentation for pulmonary embolism and the length of hospital stay. We used logistic models to study the association between hospital volume and 30-day mortality and discrete survival models to study the association between in-hospital mortality and time to hospital discharge.

RESULTS

The median annual hospital volume for pulmonary embolism was 20 patients (interquartile range 10-42). Overall in-hospital mortality was 6.0%, whereas 30-day mortality was 9.3%. In multivariable analysis, very-high-volume hospitals (> or = 42 cases per year) had a significantly lower odds of in-hospital death (odds ratio [OR] 0.71, 95% confidence interval [CI] 0.51-0.99) and of 30-day death (OR 0.71, 95% CI 0.54-0.92) than very-low-volume hospitals (< 10 cases per year). Although patients in the very-high-volume hospitals had a slightly longer length of stay than those in the very-low-volume hospitals (mean difference 0.7 days), there was no association between volume and length of stay.

INTERPRETATION

In hospitals with a high volume of cases, pulmonary embolism was associated with lower short-term mortality. Further research is required to determine the causes of the relation between volume and outcome for patients with pulmonary embolism.