Absolute Risk Of Venous Thromboembolism Research Articles

OA38 Venous thromboembolism risk is consistently increased in people with rheumatoid arthritis across different ages, sexes and obesity status: United Kingdom population-based study

Abstract Background/Aims Risk of venous thromboembolism (VTE) is increased in people with rheumatoid arthritis (RA) when compared to the general population, but the variation of this risk among patients is not well understood. Acknowledging the heterogeneity in RA-attributable VTE risk could support tailoring of treatment plans and screening protocols based on an individual’s specific risk profile. In a large population-based study, we aimed to evaluate for variation in RA-attributable VTE risk by age, sex and body-mass index (BMI). Methods Adults registered with a general practice from January 1999 to December 2018 were identified from the Royal College of General Practitioners Research (RCGP) and Surveillance Centre (RSC) primary care database. RA patients and VTE outcome (composite of pulmonary embolism and deep vein thrombosis) were determined using previously validated algorithms. RA-unaffected controls (UCs) were matched 4:1 with RA patients by current age, sex, calendar time, and years since practice registration using nearest neighbour matching with replacement. Absolute VTE rates over 20 years were compared in RA patients versus matched UCs, overall and by age category (18-49, 50-69, ≥70), sex, and BMI category (BMI <25, 25-29.9, ≥30). Across the same subgroups, relative VTE risk over the same period was estimated using Cox proportional hazards models adjusted for sociodemographic and clinical features and established VTE risk factors (BMI, smoking status, alcohol use, evidence of reduced mobility, thrombophilia, fracture of the lower limb and family history of VTE). Results 117,050 individuals were included, of whom 23,410 were RA patients and 93,640 were UCs. Average follow-up was 8.2 years (standard deviation [SD]=6.6 years). RA patients (mean age 59.0, SD 15.5; 28.9% male [n = 6776]; mean BMI 27.1, SD 5.6) were similar to matched UCs in clinical characteristics. Unadjusted VTE events rates were consistently higher in RA patients compared to UCs overall and across all subgroups (overall rates RA: 442.4 per 100,000 person-years [py], 95% confidence interval [CI]: 413.0, 473.2; UC: 262.2 per 100,000 py, 95%CI: 251.9, 273.9); subgroup rates). Similarly, overall relative VTE risk was 46% higher in people with RA compared to UCs (adjusted hazard ratio [aHR]= 1.46, 95%CI: 1.36, 1.56; p < 0.001), and was consistently higher across age-, sex- and BMI-defined subgroups (aHR range: 1.34-2.13, all p < 0.001). Although relative risk was highest in RA patients under 50 years (aHR= 2.13, 95%CI: 1.62-2.79; p < 0.001), this patient subgroup had the lowest absolute risk of VTE (approximately 2.2- and 3.4-fold lower than that observed in those aged 50-69 and ≥70, respectively). Conclusion Clinicians should be aware that risk of VTE is consistently higher in people with RA compared to the general population, regardless of age, sex and BMI. Findings suggest close monitoring and assessment of VTE risk factors is required even in younger individuals with RA. Disclosure J. Galloway: Honoraria; JG has received honoraria from Abbvie, Biovitrum, BMS, Celgene, Chugai, Gilead, Janssen, Lilly, Novartis, Pfizer, Roche, Sanofi, Sobi and UC. V. Basey: Corporate appointments; Pfizer employee. M. Mclean: Corporate appointments; Pfizer employee. S. de Lusignan: Grants/research support; SdeL has received funding through his universities from Eli Lilly, GSK, Astra Zeneca, MSD, Sanofi, Seqirus, Takeda and Moderna. Other; Director of the RCGP RSC. M.H. Buch: Consultancies; M.H.B. has provided expert advice and received/paid to employer consultant fees from AbbVie, Eli Lilly, EMD serono, Gilead, Pfizer and Sanofi. Grants/research support; M.H.B. has received research grants paid to her employer from Gilead Ltd, Pfizer Ltd, Roche and UCB.

Risk of arterial and venous thrombotic events among patients with cancer diagnosed with COVID-19: A real-world data analysis

AimThe risk of venous thromboembolism (VTE) and arterial thrombosis events (ATE) and potential corresponding risk factors were assessed in patients with cancer diagnosed with COVID-19. MethodsAdults with cancer treated in community health systems who were diagnosed with COVID-19 in 2020 were evaluated for absolute risk (risk) of ATE and VTE. Thrombotic events were ascertained in the 90-day window starting with COVID-19 diagnosis (index). ICD codes defined baseline comorbidities, COVID-19, and thrombotic events. Results7591 patients were included with median age of 67, 6% with cardiovascular disease (CVD), 4% with prior VTE, and 24% were hospitalized at index. Risk of ATE and VTE were 2.1% (95%CI: 1.8, 2.5) and 3.2% (95%CI: 2.8, 3.6), respectively. Patients with CVD had increased risk [ATE: 20.1% (95%CI: 16.7, 24.1); VTE: 4.9% (95%CI: 3.3, 7.3)] as did patients with prior VTE [ATE: 3.8% (95%CI: 2.2, 6.6; VTE: 20.5% (95%CI: 16.4, 25.3)] and patients hospitalized with ventilator support [(ATE: 5.7% (95%CI: 2.6, 11.8; VTE: 6.6% (95%CI: 3.2, 13.0)]. Incidence rates for ATE and VTE were 0.094 and 0.141 per person-year, respectively. ConclusionsThis study of cancer patients, conducted in a time period prior to vaccine availability, found patients with CVD, prior VTE, and with higher severity of COVID-19 were at increased risk for ATE and VTE. Identifying patients most at risk can help to target interventions.

Risk of venous thromboembolism in pregnant patients with active malignancy: A systematic review and meta-analysis.

Cancer currently occurs in about 1 in 1000 pregnancies. Both active malignancy and pregnancy are individual risk factors for venous thromboembolism (VTE). The purpose of this systematic review/meta-analysis was to evaluate the rate of VTE in pregnant patients with active malignancy compared with pregnant patients without malignancy. Embase, Medline/PubMed, Cochrane Database, and clinicaltrial.gov were search by a trained librarian from inception until June 2021, and limited to English and French language human studies using keywords related to pregnancy, neoplasm, and thrombosis. This study was prospectively registered with PROSPERO (CRD42021245886). Title, abstract, and full-text review was performed using the Covidence data management system. Two authors reviewed the studies independently. Of the 3821 articles screened, seven cohort studies were included that reported VTE rate in patients with active malignancy in pregnancy. A total of 5928 individuals had active malignancy and pregnancy. Active malignancy in pregnancy significantly increased the odds of a VTE (odds ratio [OR] 6.8, 95% confidence interval [CI] 3.8-12.1). Specifically, patients with thyroid (OR 2.7, 95% CI 1.3-6.3), cervix (OR 6.6, 95% CI 2.4-18.0), or other gynecological (OR 10.6, 95% CI 4.4-25.8) cancers; Hodgkin's lymphoma (OR 8.7, 95% CI 3.3-23.4); or acute leukemia (OR 17.1, 95% CI 10.9-26.8) all had increased odds, whereas those with brain cancer (OR 6.1, 95% CI 0.4-98.2), breast cancer (OR 2.5, 95% CI 0.3-17.4), malignant melanoma (OR 5.5, 95% CI 0.3-88.1), or non-Hodgkin's lymphoma (OR 3.2, 95% CI 0.8-12.9) malignancies did not have statistically significant increased odds for VTE. No studies reported whether prophylactic anticoagulation was used during pregnancy in this population; nor did they report timing in pregnancy of the VTE. The absolute risk for VTE in those with active malignancy was 0.9% compared with 0.2% in those without active malignancy in pregnancy. Pregnancy with active malignancy confers a significant increased risk for VTE compared with pregnancy alone. Given this finding, prophylactic anticoagulation during pregnancy and postpartum could be considered in this patient population. Data are underpowered to make firm recommendations per cancer type.

Risk of admission to hospital with arterial or venous thromboembolism among patients diagnosed in the ambulatory setting with covid-19 compared with influenza: retrospective cohort study

ObjectiveTo measure the 90 day risk of arterial thromboembolism and venous thromboembolism among patients diagnosed with covid-19 in the ambulatory (ie, outpatient, emergency department, or institutional) setting during periods before...

Assessment of the Risk of Venous Thromboembolism in Nonhospitalized Patients With COVID-19

Patients hospitalized with COVID-19 have higher rates of venous thromboembolism (VTE), but the risk and predictors of VTE among individuals with less severe COVID-19 managed in outpatient settings are less well understood. To assess the risk of VTE among outpatients with COVID-19 and identify independent predictors of VTE. A retrospective cohort study was conducted at 2 integrated health care delivery systems in Northern and Southern California. Data for this study were obtained from the Kaiser Permanente Virtual Data Warehouse and electronic health records. Participants included nonhospitalized adults aged 18 years or older with COVID-19 diagnosed between January 1, 2020, and January 31, 2021, with follow-up through February 28, 2021. Patient demographic and clinical characteristics identified from integrated electronic health records. The primary outcome was the rate per 100 person-years of diagnosed VTE, which was identified using an algorithm based on encounter diagnosis codes and natural language processing. Multivariable regression using a Fine-Gray subdistribution hazard model was used to identify variables independently associated with VTE risk. Multiple imputation was used to address missing data. A total of 398 530 outpatients with COVID-19 were identified. The mean (SD) age was 43.8 (15.8) years, 53.7% were women, and 54.3% were of self-reported Hispanic ethnicity. There were 292 (0.1%) VTE events identified over the follow-up period, for an overall rate of 0.26 (95% CI, 0.24-0.30) per 100 person-years. The sharpest increase in VTE risk was observed during the first 30 days after COVID-19 diagnosis (unadjusted rate, 0.58; 95% CI, 0.51-0.67 per 100 person-years vs 0.09; 95% CI, 0.08-0.11 per 100 person-years after 30 days). In multivariable models, the following variables were associated with a higher risk for VTE in the setting of nonhospitalized COVID-19: age 55 to 64 years (HR 1.85 [95% CI, 1.26-2.72]), 65 to 74 years (3.43 [95% CI, 2.18-5.39]), 75 to 84 years (5.46 [95% CI, 3.20-9.34]), greater than or equal to 85 years (6.51 [95% CI, 3.05-13.86]), male gender (1.49 [95% CI, 1.15-1.96]), prior VTE (7.49 [95% CI, 4.29-13.07]), thrombophilia (2.52 [95% CI, 1.04-6.14]), inflammatory bowel disease (2.43 [95% CI, 1.02-5.80]), body mass index 30.0-39.9 (1.57 [95% CI, 1.06-2.34]), and body mass index greater than or equal to 40.0 (3.07 [1.95-4.83]). In this cohort study of outpatients with COVID-19, the absolute risk of VTE was low. Several patient-level factors were associated with higher VTE risk; these findings may help identify subsets of patients with COVID-19 who may benefit from more intensive surveillance or VTE preventive strategies.

Association of COVID-19 vs Influenza With Risk of Arterial and Venous Thrombotic Events Among Hospitalized Patients

The incidence of arterial thromboembolism and venous thromboembolism in persons with COVID-19 remains unclear. To measure the 90-day risk of arterial thromboembolism and venous thromboembolism in patients hospitalized with COVID-19 before or during COVID-19 vaccine availability vs patients hospitalized with influenza. Retrospective cohort study of 41 443 patients hospitalized with COVID-19 before vaccine availability (April-November 2020), 44 194 patients hospitalized with COVID-19 during vaccine availability (December 2020-May 2021), and 8269 patients hospitalized with influenza (October 2018-April 2019) in the US Food and Drug Administration Sentinel System (data from 2 national health insurers and 4 regional integrated health systems). COVID-19 or influenza (identified by hospital diagnosis or nucleic acid test). Hospital diagnosis of arterial thromboembolism (acute myocardial infarction or ischemic stroke) and venous thromboembolism (deep vein thrombosis or pulmonary embolism) within 90 days. Outcomes were ascertained through July 2019 for patients with influenza and through August 2021 for patients with COVID-19. Propensity scores with fine stratification were developed to account for differences between the influenza and COVID-19 cohorts. Weighted Cox regression was used to estimate the adjusted hazard ratios (HRs) for outcomes during each COVID-19 vaccine availability period vs the influenza period. A total of 85 637 patients with COVID-19 (mean age, 72 [SD, 13.0] years; 50.5% were male) and 8269 with influenza (mean age, 72 [SD, 13.3] years; 45.0% were male) were included. The 90-day absolute risk of arterial thromboembolism was 14.4% (95% CI, 13.6%-15.2%) in patients with influenza vs 15.8% (95% CI, 15.5%-16.2%) in patients with COVID-19 before vaccine availability (risk difference, 1.4% [95% CI, 1.0%-2.3%]) and 16.3% (95% CI, 16.0%-16.6%) in patients with COVID-19 during vaccine availability (risk difference, 1.9% [95% CI, 1.1%-2.7%]). Compared with patients with influenza, the risk of arterial thromboembolism was not significantly higher among patients with COVID-19 before vaccine availability (adjusted HR, 1.04 [95% CI, 0.97-1.11]) or during vaccine availability (adjusted HR, 1.07 [95% CI, 1.00-1.14]). The 90-day absolute risk of venous thromboembolism was 5.3% (95% CI, 4.9%-5.8%) in patients with influenza vs 9.5% (95% CI, 9.2%-9.7%) in patients with COVID-19 before vaccine availability (risk difference, 4.1% [95% CI, 3.6%-4.7%]) and 10.9% (95% CI, 10.6%-11.1%) in patients with COVID-19 during vaccine availability (risk difference, 5.5% [95% CI, 5.0%-6.1%]). Compared with patients with influenza, the risk of venous thromboembolism was significantly higher among patients with COVID-19 before vaccine availability (adjusted HR, 1.60 [95% CI, 1.43-1.79]) and during vaccine availability (adjusted HR, 1.89 [95% CI, 1.68-2.12]). Based on data from a US public health surveillance system, hospitalization with COVID-19 before and during vaccine availability, vs hospitalization with influenza in 2018-2019, was significantly associated with a higher risk of venous thromboembolism within 90 days, but there was no significant difference in the risk of arterial thromboembolism within 90 days.

Preperitoneal Pelvic Packing for Hypotension Has a Greater Risk of Venous Thromboembolism Than Angioembolization: Management of Refractory Hypotension in Closed Pelvic Ring Injury.

Patients with traumatic pelvic ring injury may present with hypotension secondary to hemorrhage. Preperitoneal pelvic packing (PPP) and angioembolization (AE) are alternative interventions for management of hypotension associated with pelvic ring injury refractory to resuscitation and circumferential compression. We hypothesized that PPP may be independently associated with increased risk of venous thromboembolism (VTE) compared with AE in patients with hypotension and pelvic ring injury. Adult patients with pelvic ring injury and hypotension managed with PPP or AE were retrospectively identified in the Trauma Quality Improvement Program (TQIP) database from 2015 to 2019. Patients were matched on a propensity score for receiving PPP based on patient, injury, and treatment factors. The primary outcome was the risk of VTE after matching on the propensity score for treatment. The secondary outcomes included inpatient clinically important deep vein thrombosis, pulmonary embolism, respiratory failure, mortality, unplanned reoperation, sepsis, surgical site infection, hospital length of stay, and intensive care unit (ICU) length of stay. In this study, 502 patients treated with PPP and 2,439 patients treated with AE met inclusion criteria. After propensity score matching on age, smoking status, Injury Severity Score, Tile B or C pelvic ring injury, bilateral femoral fracture, serious head injury, units of plasma and platelets given within 4 hours of admission, laparotomy, and level-I trauma center facility designation, 183 patients treated with PPP and 183 patients treated with AE remained. PPP, compared with AE, was associated with a 9.8% greater absolute risk of VTE, 6.5% greater risk of clinically important deep vein thrombosis, and 4.9% greater risk of respiratory failure after propensity score matching. PPP for the management of hypotension associated with pelvic ring injury is associated with higher rates of inpatient VTE events and sequelae compared with AE. Prognostic Level III . See Instructions for Authors for a complete description of levels of evidence.

Venous thrombosis risk during and after medical and surgical hospitalizations: The medical inpatient thrombosis and hemostasis (MITH) study

BackgroundThirty to seventy percent of all venous thromboembolism (VTE) events are associated with hospitalization. The absolute and relative risks during and after hospitalization are poorly characterized. ObjectivesQuantify the absolute rate and relative risk of VTE during and up to 3 months after medical and surgical hospitalizations. Patients/MethodsWe conducted an observational cohort study between 2010 and 2016 of patients cared for by the University of Vermont (UVM) Health Network's primary care population. Cox proportional hazard models with hospitalization modeled as a time‐varying covariate were used to estimate VTE risk. ResultsOver 4.3 years of follow‐up, 55 220 hospitalizations (156 per 1000 person‐years) and 713 first venous thromboembolism events (2.0 per 1000 person‐years) occurred. Among individuals not recently hospitalized, the rate of venous thromboembolism was 1.4 per 1000 person‐years and 71.8 per 1000 person‐years during hospitalization. During the first, second, and third months after discharge, the rates of venous thromboembolism were 35.1, 11.3, and 5.2 per 1000 person‐years, respectively. Relative to those not recently hospitalized, the age‐ and sex‐adjusted HRs of venous thromboembolism were 38.0 (95% CI 28.0, 51.5) during hospitalization, and 18.4 (95% CI 15.0, 22.6), 6.3 (95% CI 4.3, 9.0), and 3.0 (95% CI 1.7, 5.4) during the first, second, and third months after discharge, respectively. Stratified by medical versus surgical services the rates were similar. ConclusionHospitalization and up to 3 months after discharge were strongly associated with increased venous thromboembolism risk. These data quantify this risk for use in future studies.

Abstract 445: Natural history of coagulopathy in patients with cancer infected with COVID19: A real-world data (RWD) analysis

Abstract Background and Objective: Studies of hospitalized patients (pts) with COVID19 indicate that arterial or venous thrombotic complications occur in up to half of pts. Risk of these severe complications in pts with cancer is unknown. We estimated the incidence of arterial thrombosis (AT) and venous thromboembolism (VT) using RWD from pts with active or history of cancer with COVID19. Methods: Adult pts with cancer receiving treatment in community health systems, with COVID19 identified via ICD code or lab confirmation in 2020, were reviewed for incident AT and VT in a 90 day window following COVID19 diagnosis (index). AT was acute myocardial infarction (MI) or acute ischemic or embolic stroke (S). VT was acute deep venous thrombosis (DVT) or acute pulmonary embolism (PE). Medication use (anticoagulant, antiplatelet, statin) and comorbidities were assessed 6 months and 1 year prior to index, respectively. Results: Median age of 7,591 pts with cancer and COVID19 was 67 years and median follow up was 90 days. 32% of pts were hospitalized within 14 days, 2% received ventilator support, 6% had cardiovascular disease (CVD) and 1% had prior VT. Absolute risk of VT was significantly higher than AT (3% vs. 2%, chi square p= < 0.001), with 161 pts experiencing AT [81 (1%) MI; 80 (1%) S] and 240 pts experiencing VT [99 (1%) DVT; 158 (2%) PE]. This trend held across most subgroups (Table 1). The incidence rate per person-year was 0.094 for AT (0.047 MI, 0.046 S) and 0.141 for VT (0.058 DVT, 0.092 PE). CoxPH models did not show age, sex, comorbidities or medication use as significantly associated with higher probability of AT or VT. Conclusions: RWD showed pts with cancer and COVID19 were at higher risk for VT than AT. Pts who received ventilator support, or had prior VT or prior CVD had highest risk for these events. Severity of these outcomes emphasizes the need for risk reducing interventions. Acknowledgement of Reagan-Udall Foundation and Friends of Cancer Research COVID19 Evidence Accelerator. Table 1. Incidence of arterial and venous events stratified by baseline characteristics at COVID-19 diagnosis among n= 7,591 patients with cancer and infected with COVID19 Absolute Risk, N(%) Incidence Rate Total, N Arterial thrombosis Venous thromboembolism Chi square p-value Arterial thrombosis Venous thromboembolism p-value All 7,591 160 (2.1) 240 (3.2) <0.001 0.0935 0.1414 <0.001 Age 18-44 669 10 (1.5) 10 (1.5) 0.008 0.012 0.061 0.020 45-54 922 4 (0.4) 18 (2) 0.018 0.08 0.003 55-64 1751 26 (1.5) 54 (3.1) 0.062 0.129 0.001 65-74 2054 49 (2.4) 78 (3.8) 0.104 0.165 0.008 75-84 1506 55 (3.7) 60 (4) 0.169 0.184 0.557 85+ 689 24 (3.5) 20 (2.9) 0.18 0.15 0.542 Sex Female 4142 75 (1.8) 126 (3) 0.338 0.078 0.131 0.000 Male 3449 85 (2.5) 114 (3.3) 0.11 0.148 0.030 Race Black 1437 31 (2.2) 61 (4.2) 0.215 0.095 0.187 0.001 White 5054 113 (2.2) 157 (3.1) 0.098 0.137 0.003 Other/Unknown 1100 16 (1.5) 22 (2) 0.061 0.084 0.724 Severity of infection at diagnosis Not hospitalized 5815 78 (1.3) 141 (2.4) 0.0676 0.06 0.105 <0.001 Hospitalized, no ventilator support 1710 76 (4.4) 92 (5.4) 0.21 0.261 0.143 Hospitalized with ventilator support 106 6 (9.1) 7 (10.6) 0.326 0.326 0.965 Existing Cardiovascular disease Yes 467 94 (20.2) 23 (4.9) <0.001 0.105 0.06 <0.001 No 7124 66 (0.9) 217 (3) 0.21 0.261 <0.001 And baseline anticoagulant use 122 27 (22.1) 9 (7.4) <0.001 0.326 0.326 0.602 And no baseline anticoagulant use 7469 67 (19.5) 14 (4.1) 0.088 0.054 <0.001 Previous Venous thromboembolism Yes 312 12 (3.8) 64 (20.5) <0.001 0.184 0.981 <0.001 No 7279 148 (2.0) 176 (2.3) 0.089 0.105 0.542 And baseline anticoagulant use 121 9 (4.7) 22 (11.6) 0.273 0.397 0.969 <0.001 And no baseline anticoagulant use 7470 3 (1.6) 42 (22.1) 0.088 0.127 0.003 Existing Thrombocytosis (via ICD or platelet count >450 x 10^9/L) Yes 185 5 (2.7) 7 (3.8) 1 0.123 0.172 0.087 No 7406 155 (2.1) 233 (3.1) 0.091 0.137 <0.001 Citation Format: Jeanna Wallenta Law, Danny Idyro, Andrew Schrag, Frank Wolf, Thomas D. Brown. Natural history of coagulopathy in patients with cancer infected with COVID19: A real-world data (RWD) analysis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 445.

A151 RISK FACTORS FOR VENOUS THROMBOEMBOLISM AFTER HOSPITAL DISCHARGE IN PATIENTS WITH INFLAMMATORY BOWEL DISEASE: A SYSTEMATIC REVIEW AND META-ANALYSIS

BackgroundInflammatory bowel disease (IBD) is a chronic inflammatory condition which is independently associated with venous thromboembolism (VTE). Although the absolute risk of VTE is greatest during hospitalization, the risk remains elevated in the early post-discharge period. The risk factors for VTE during this vulnerable period remain unknown.AimsWe performed a systematic review and meta-analysis to determine risk factors for VTE in the post discharge period among adult patients with IBD.MethodsWe performed a systematic search of Embase, MEDLINE, and the Cochrane Central Register of Controlled Trials from inception through April 29, 2021 for publications that reported risk factors for VTE during the post-discharge period among patients with IBD. Study eligibility was assessed independently in duplicate without age or language restriction. We defined the post-discharge period as within 6 months of discharge. Pooled summary estimates of adjusted hazard/odds ratios, when available, were calculated for individual risk factors using random effects model with 95% confidence intervals. The analysis was performed when a minimum of three studies were available for a given risk factor. Heterogeneity was assessed using I2 statistic. Study quality was assessed using an adapted version of the National Institute of Health criteria.ResultsWe identified 10 studies from a total of 4339 abstracts that met our inclusion criteria: 8 population-based studies, 1 multicenter observational study and 1 single center observational study. Risk factors for post-discharge VTE were assessed at 6 weeks in 1 study, 1 month in 5 studies, 3 months in 2 studies, and 6 months in 2 studies. The variables assessed in our meta-analysis are reported in Table 1. Exposure to corticosteroid (odds ratio [OR], 1.77; 95% CI, 1.53–2.06) but not biologics (OR, 1.21; 95% CI 0.80–1.82) was associated with an increased risk of VTE. Furthermore, greater length of stay (OR 1.49; 95% CI, 1.01–2.20), ulcerative colitis (OR 1.41; 95% CI, 1.19–1.66), history of malignancy (OR 1.35; 95% CI, 1.12–1.62), and surgery during admission (OR 1.26; 95% CI, 1.12–1.42) but not female sex (OR 0.98; 95% CI, 0.88–1.10) or surgery type (OR 1.09; 95% CI, 0.75–1.57) were associated with increased risk of VTE after discharge. Overall, the study quality was rated as fair.ConclusionsIn our meta-analysis, which consisted of moderate quality of evidence, we identified multiple risk factors associated with VTE in the post-discharge period. This work will help inform which factors should be considered for developing point of care clinical predictive models to help guide when extended VTE prophylaxis is required. Funding AgenciesNone

α1‐Antitrypsin Z allele and risk of venous thromboembolism in the general population

BackgroundThe α1‐antitrypsin Z (rs28929474) allele may lead to alterations in hemostasis either through liver disease or effects on coagulation factors. ObjectivesTo test the hypothesis that the α1‐antitrypsin Z genetic variant is associated with increased risk of venous thromboembolism. MethodsA total of 107 075 individuals from the Copenhagen General Population Study were used to test the association of the α1‐antitrypsin Z genetic variant with risk of venous thromboembolism, including deep venous thrombosis and pulmonary embolism, prospectively. Confirmatory analyses were done in the UK Biobank. ResultsDuring follow‐up, venous thromboembolism was diagnosed 6649 times in noncarriers, 436 times in heterozygotes, and 10 times in homozygotes. Hazard ratios for venous thromboembolism in α1‐antitrypsin Z heterozygotes and homozygotes versus noncarriers were 1.1 (95% confidence interval, 1.0–1.2) and 2.2 (1.3–3.7). A one Z allele increase was associated with a hazard ratio for venous thromboembolism of 1.2 (1.0–1.3). The corresponding odds ratio in the UK Biobank was 1.2 (1.1–1.3). The absolute risk of venous thromboembolism associated with α1‐antitrypsin ZZ homozygosity was 7.8% (3.6–12.1). The corresponding estimates were 20.1% (9.1–31.2) for prothrombin G20210A and 15.0% (12.6–17.4) for factor V Leiden. The fraction of venous thromboembolic events attributable to the α1‐antitrypsin Z allele was 0.7% (0.1–1.3). For the prothrombin G20210A and factor V Leiden mutations, population attributable fractions were 1.2% (0.9–1.6) and 10.5% (9.9–11.1). ConclusionIn conclusion, α1‐antitrypsin ZZ homozygosity was associated with a 2.2‐fold risk of venous thromboembolism and had a comparable population attributable fraction to prothrombin G20210A.

Bleeding Risk in Patients with Multiple Myeloma Treated for Venous Thromboembolism

▪Introduction:Multiple myeloma diagnosis is associated with a 10-15% absolute risk of venous thromboembolism (VTE) due to disease-related (i.e., vascular inflammation, hyperviscosity) and treatment-related risk factors (i.e., immunomodulatory drugs [IMiDs], high-dose dexamethasone). This has led to ongoing clinical trials to determine the best thromboprophylaxis strategy. In contrast, the risk of major bleeding following incident VTE events in patients with MM is not well described. We conducted a real-world analysis of bleeding complications in MM following anticoagulation treatment for VTE.Methods:The IBM MarketScan Commercial Claims Database was used to identify adults with MM diagnosis and an incident VTE event between 2011 and 2019. MM and VTE were defined as 1 inpatient or 2 outpatient claims based on International Classification of Diseases (ICD) 9th and 10 th Revision codes, and at least 1 prescription for anticoagulation within 31 days of first VTE claim. IMiD-related VTE was defined in subjects with an IMiD prescription prior to the VTE event. Major bleeding was defined as bleeding requiring hospitalization using inpatient ICD codes as previously validated (Cunningham algorithm). Patients were followed from index VTE and initiation of anticoagulation to first major bleeding event, disenrollment (due to death or other reasons) or December 31, 2019. Descriptive statistics were used to calculate the rate of major bleeding. Cox regression was used to determine risk factors associated with major bleeding.Results:Our population included 1,605 patients with a diagnosis of multiple myeloma and an incident VTE event requiring treatment. Anticoagulant agent of choice was warfarin in 45.7% (734), low-molecular weight heparin (LMWH) in 29% (466), and direct oral anticoagulants (DOAC) in 25.3% (405). There were no significant differences in age/sex distribution, comorbidity burden, history of significant bleeding, or use of IMiD across the different types of anticoagulation (Table 1). Hospitalized bleeding occurred in 63 (3.9%) patients during an average follow-up of 1.6 years, yielding an overall incidence rate of major bleeding in multiple myeloma patients starting anticoagulation for a new VTE event of 24.1 per 1,000 person-years. Adjusting for age and sex, risk factors significantly associated with risk of major bleeding included Charlson comorbidy index [CCI] (per standard deviation [SD] increment, HR 1.29, 95%CI 1.03 - 1.62), diabetes (HR 1.71, 95%CI 1.06 - 2.92), and liver disease (HR 1.96, 95%CI 1.04 - 3.68). The use of IMiDs was not associated with increased risk of major bleeding (Table 2). The cumulative incidence of major bleeding by VTE anticoagulation strategy in multiple myeloma was 4.8% in warfarin group and 3.2% in the LMWH and DOAC groups, though the difference was not statistically significant after adjusting for age and sex. The estimated incidence rate of bleeding was 25.7, 20.1, and 25.2 per 1,000 person-years for patients treated with warfarin, LMWH, and DOACs, respectively. In an adjusted model for age, sex, CCI, diabetes and liver disease, patients treated with LMWH and DOACs had HR for major bleeding of 0.91 and 0.82, respectively, compared to anticoagulation with warfarin, though this was not statistically significant.Discussion:In a real-world analysis of commercial claims data, the rate of major bleeding in patients with multiple myeloma receiving anticoagulation for VTE appears to be comparable to those reported in other subsets of cancer associated VTE. Surprisingly, almost half of identified patients were treated with warfarin, a non-preferred option in this setting. The point estimate of major bleeding was lower in patients treated with LMWH or DOACs compared to warfarin, though the association was not statistically significant and larger studies are needed. Higher CCI, diabetes and liver disease were clinical factors associated with higher risk of major bleeding and may be included in risk assessment models to help clinicians assess individual bleeding risk in patients with multiple myeloma treated for VTE. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

Risk Assessing Medical Inpatients for Hospital-Acquired Venous Thrombosis: The Medical Inpatients Thrombosis and Hemostasis (MITH) Study

Introduction: Multiple regulatory agencies and professional societies recommend risk assessment of hospitalized medical patients for hospital-acquired (HA) venous thromboembolism (VTE) and provision of pharmacologic prophylaxis to those at risk. Extant risk assessment models (RAMs) include risk factors not knowable or difficult to assess at admission and often do not include risk factors reflecting illness acuity (such as laboratory studies and vital signs at admission). We developed a RAM for HA-VTE that reports absolute VTE risk, as opposed to arbitrary risk categories, using only objective risk factors measured within the first 24 hours of admission.Methods: The study setting was a combined academic and community 540-bed teaching hospital in northwest Vermont (The University of Vermont Medical Center). Using validated electronic health record (EHR) derived phenotypes (computable phenotypes), we captured all medical admissions between 2010-2019 and examined patient demographics, past medical history, and presenting vital and laboratory measures as potential risk factors for HA-VTE. As risk assessment should happen within 24 hours of admission, we only assessed risk factors knowable within this timeframe. Individuals with VTE at admission were excluded. Key outcome and risk factor definitions were validated using chart review. Bayesian logistic regression with a least absolute shrinkage and selection operator (LASSO) prior probability distribution was used to select risk factors for the model. Variables with a t-statistic ≥1.5 or ≤-1.5 were included in the final model. Full or prophylactic anticoagulation use was adjusted for in the final model. Model performance was assessed using bootstrap resampling to estimate area under the receiver operating characteristic (AUC) curve and calibration slope with 95% confidence interval (CI).Results: There were 62,468 medical admissions in the study period with 219 HA-VTE events. Chart review demonstrated the positive predictive value of our HA-VTE computable phenotype to be 84% and the negative predictive value 99%. Mean age was 65 years and 51% were male. Comorbid conditions were common in this hospitalized population, including active cancer (29%), congestive heart failure (25%), diabetes (27%), hypertension (59%), and prior myocardial infarction (13%). Seven risk factors met the criteria for inclusion in the final model: prior history of VTE (OR 2.7; 95% CI 1.8, 3.8), red cell distribution width ≥14.7% (OR 1.6; 95% CI 1.2, 2.2), creatinine ≥2.0 mg/dL or on dialysis (OR 2.0; 95% CI 1.4, 2.8), serum sodium <136 MEq/L (OR 1.5; 95% CI 1.1, 2.1), active cancer (OR 1.4; 95% CI 1.1, 2.0), malnutrition based on prior reported weight loss (OR 2.1; 95% CI 1.3, 3.3), and low hemoglobin (<13.6 g/dL in men, <12.1 g/dL in women; OR 1.5; 95% CI 1.0, 2.1). The unadjusted AUC of the RAM was 0.73 with an unadjusted calibration slope 1.09 (Figure 1). The optimism-adjusted AUC was 0.68 (95% CI 0.64, 0.71) and the optimism-adjusted calibration slope was 0.87 (95% CI: 0.72, 1.03).Discussion: We developed and internally validated a RAM for HA-VTE during medical hospitalization which incorporates simple, objective risk factors knowable within the first 24 hours of admission. Unlike most prior RAMs, this model also incorporates risk factors reflecting illness severity such as laboratory results. The RAM has good fit and calibration and will be moved forward to external validation. Future applications include incorporating the RAM into hospital admission workflows and assessing VTE prophylaxis rates and the incidence of HA-VTE and HA-bleeding. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

Comorbidity and risk of venous thromboembolism after hospitalization for first‐time myocardial infarction: A population‐based cohort study

BackgroundMyocardial infarction (MI) is a risk factor for venous thromboembolism (VTE). Although comorbidities affect MI prognosis, it is unclear whether they affect VTE risk after MI. ObjectivesWe examined the impact of comorbidity on VTE risk after MI. MethodsWe used nationwide population‐based registries to identify first‐time hospitalizations for MI and subsequent occurrence of VTE in Denmark (1995‐2013). We included a comparison cohort from the general population matched 5:1 with MI patients by sex, age, and comorbidities. We computed 30‐day and 1‐ to 12‐month cumulative risks, rates, and hazard ratios of VTE. We also assessed the interaction between MI and comorbidity, defined as excess VTE risk in patients with both MI and comorbidity, by computing interaction contrasts and attributable fractions relating to the interaction. ResultsThirty‐day and 1‐ to 12‐month VTE risks were 0.6% and 0.5% in the MI cohort (n = 160 338) and 0.03% and 0.3% in the comparison cohort (n = 792 384). The 30‐day hazard ratio for VTE in the MI cohort was 23 (95% confidence interval, 20‐27), which decreased during 1‐year follow‐up. Thirty days after MI, interactions between MI and comorbidity accounted for 16% and 39% of VTE rates in MI patients with low‐to‐moderate and high comorbidity, respectively. The interactions were driven primarily by hemiplegia and cancer. ConclusionsThirty‐day VTE risk was substantially increased after MI compared with the general population. Although the absolute VTE risk was low, comorbidity substantially increased this risk, especially hemiplegia and cancer. VTE prophylaxis might be indicated in such high‐risk patients but warrants further investigation.

OP0034 DOES THE RISK OF VENOUS THROMBOEMBOLISM VARY WITH DISEASE ACTIVITY IN RHEUMATOID ARTHRITIS?

Background:Patients with rheumatoid arthritis (RA) are at increased risk for venous thromboembolism (VTE), including deep vein thrombosis (DVT) and pulmonary embolism (PE) (1). Several established risk factors of VTE, such as age, immobilization and comorbid conditions, occur more often patients with RA (2). In addition, inflammation may in itself also increase VTE risk by upregulating procoagolatory factors and causing endothelial damage (3). Recent reports indicate an increased risk of VTE in RA patients treated with JAK-inhibitors (4), pointing to the need to better understand how inflammation measured as clinical RA disease activity influences VTE risk.Objectives:To investigate the relationship between clinical RA disease activity and incidence of VTE.Methods:Patients with RA were identified from the Swedish Rheumatology Quality Register (SRQ) between July 1st2006 and December 31st2017. Clinical rheumatology data for these patients were obtained from the visits recorded in SRQ, and linked to national registers capturing data on VTE events and comorbid conditions. For each such rheumatologist visit, we defined a one-year period after the visit and determined whether a VTE event had occurred within this period or not. A visit followed by a VTE event was categorized as a case, all other visits were used as controls. Each patient could contribute to several visits. The DAS28 score registered at the visit was stratified into remission (0-2.5) vs. low (2.6-3.1), moderate (3.2-5.1) and high (&gt;5.1) disease activity. Logistic regression with robust cluster standard errors was used to estimate the association between the DAS28 score and VTE.Results:We identified 46,311 patients with RA who contributed data from 320,094 visits. Among these, 2,257 visits (0.7% of all visits) in 1345 unique individuals were followed by a VTE within the one-year window. Of these, 1391 were DVT events and 866 were PE events. Figure 1 displays the absolute probabilities of a VTE in this one-year window, and odds ratios for VTE by each DAS28 category, using DAS28 remission as reference. The one-year risk of a VTE increased from 0.5% in patients in DAS28 remission, to 1.1% in patients with DAS28 high disease activity (DAS28 above 5.1). The age- and sex-adjusted odds ratio for a VTE event in highly active RA compared to RA in remission was 2.12 (95% CI 1.80-2.47). A different analysis, in which each patient could only contribute to one visit, yielded similar results.Figure 1.Odds ratios (OR) comparing the odds of VTE for DAS28 activity categories versus remission. Grey estimates are from unadjusted logistic regression models, black estimates are from logistic regression models adjusted for age and sex. Absolute one-year risk of VTE are estimated from unadjusted models.Conclusion:This study demonstrates a strong association between clinical RA inflammatory activity as measured through DAS28 and risk of VTE. Among patients with high disease activity one in a hundred will develop a VTE within the coming year. These findings highlight the need for proper VTE risk assessment in patients with active RA, and confirm that patients with highly active RA, such as those recruited to trials for treatment with new drugs, are already at particularly elevated risk of VTE.

Optimal duration of Vitamin K antagonists anticoagulant therapy after venous thromboembolism: a systematic review and network meta-analysis of randomized controlled trials

BackgroundThe optimal duration of oral anticoagulant therapy for patients with venous thromboembolism (VTE) remains highly uncertain in clinical practice. It is essential to accurately assess the effect of anticoagulant therapy in reducing recurrent VTE against the risk of inducing major bleeding.MethodsRandomized controlled trials were identified by searching PubMed, Web of Science, Embase, and the Cochrane library, reporting rates of recurrent VTE and major bleeding in patients taking Vitamin K Antagonists (VKA) with VTE and comparing different durations.ResultsEleven RCTs with 3109 participants utilizing varied durations were included in the meta-analysis. Longer VKA therapy was associated with significantly lower rates of VTE recurrence compared with shorter duration of VKA therapy (OR 0.75, 95%CI 0.57–0.99), with significant difference noted in major bleeding risk (OR 2.31, 95%CI 1.17–4.56). During anticoagulation duration, patients treated by 6-month VKA had higher risk of major bleeding compared with 3-month VKA regimen (OR 33.45, 95%CI 2.00–559.67).ConclusionsRegimen longer than 6 months did not show statistical elevation of major bleeding risk. VKA treatment strongly reduces the risk of recurrent VTE during anticoagulation therapy. The absolute risk of recurrent VTE declines over time while the risk for major bleeding after 6 months’ treatment did not demonstrate a continuous significant increase with extended duration of VKA therapy.

The risk and prevention of venous thromboembolism in the pregnant traveller.

The average risk of venous thromboembolism (VTE) in long haul travellers is approximately 2.8 per 1000 travellers, which is increased in the presence of other VTE risk factors. In pregnant long-haul travellers, little is known in terms of the absolute risk of VTE in these women and, therefore, there is limited consensus on appropriate thromboprophylaxis in this setting. This review will provide guidance to allow practitioners to safely minimize the risk of travel-related VTE in pregnant women. The suggestions provided are based on limited data, extrapolated risk estimates of VTE in pregnant travellers and recommendations from published guidelines. We found that the absolute VTE risk per flight appears to be <1% for the average pregnant or postpartum traveller. In pregnant travellers with a prior history of VTE, a potent thrombophilia or strong antepartum risk factors (e.g. combination of obesity and immobility), the risk of VTE with travel appears to be >1%. Postpartum, the risk of VTE with travel may be >1% for women with thrombophilias (particularly in those with a family history) and other transient risk factors and in women with a prior VTE. Based on our findings, we recommend simple measures be taken by all pregnant travellers, such as frequent ambulation, hydration and calf exercises. In those at an intermediate risk, we suggest a consideration of 20-30mmHg compression stockings. In the highest risk group, we suggest careful consideration for low-molecular-weight heparin thromboprophylaxis. If there are specific concerns, we advise consultation with a thrombosis expert at the nearest local centre.

Post Discharge Risk of Venous Thromboembolism in a Primary Care Population

Introduction: Among all venous thromboembolism (VTE) events, 20% occur during or in the three months following a hospitalization. Inpatient VTE prevention strategies incorporate pharmacological interventions that do not commonly continue after discharge. Recent trials of post-discharge prophylaxis have not identified benefit among recently discharged patients, probably due to lack of understanding of the relative and absolute risks of VTE after discharge. In order to better clarify the scope of the problem, we quantified the risk of VTE during hospitalizations, and up to 3 months post-discharge relative to patients without a recent hospitalization. Methods: We followed all primary care patients aged ≥18, at the University of Vermont Medical Center's primary care clinics for hospitalization and VTE using the electronic medical record. Patients entered the cohort at their first contact with the health system after 06/30/2010 and were followed until their last contact, change of primary care provider to a non-University of Vermont provider, or December 2016, whichever occurred first. First VTE during follow-up was defined as having two outpatient VTE codes 7-185 days apart or one inpatient code. Patients with a VTE code in the first 3 months of enrollment were excluded as having pre-baseline VTE. Hospital-acquired VTE was defined as VTE occurring after day 1 of hospitalization (to correctly categorize people with an outpatient VTE and admitted with VTE) and post-discharge VTE was defined as VTE occurring during successive 1-month time periods after discharge from the hospital. Age- and sex-adjusted Cox proportional hazard models were used to calculate hazard ratios (HRs) of VTE during and after hospitalization. Hospitalization and time periods after hospitalization were modeled as time-varying covariates and included the time in the hospital, and 1-30 (month 1), 31-60 (month 2), and 61-90 (month 3) days post-discharge. The reference group for this analysis was outpatients who were not within 90 days of a hospitalization. Results: From 2010-16, 87,821 patients (49,468 women, 56%) were included, with a mean age of 46 years. With 371,429 person-years of follow-up (mean follow-up 4.2 years), 749 first VTE events occurred for a rate of 2.0 per 1,000 person-years. There were 57,837 hospitalizations among 21,963 individuals for a rate 155.7 hospitalizations per 1,000 person-years. The Table presents the person-years of follow-up, the number, rate, and age- and sex-adjusted hazard of VTE for hospitalization and successive months after hospitalization. The VTE rate was 1.5 per 1,000 person-years outpatients not within 3 months of hospitalization. During hospitalization, the rate was 75.9 per 1,000 person-years, and slowly decreased over time after discharge, but remained elevated at 5.0 per 1,000 person-years event in month 3 after discharge. The age- and sex-adjusted HR for VTE was 40.3 during hospitalization and declined to 18.1, 6.0 and 2.9 over successive 1-month intervals after discharge (Table). Conclusion: In a primary care population in northern Vermont, hospitalization and time periods after hospitalization were associated with a dramatically increased incidence of and risk for VTE compared with patients not hospitalized in the past 3 months. The rate of VTE (34.4 per 1,000 person-years) in the first month post-discharge might not warrant universal post-discharge VTE prophylaxis, but suggests that if we can identify high-risk patients at low risk for bleeding, pharmacologic VTE prophylaxis may be appropriate in some patients. Further study of risk factors for post-discharge VTE is warranted. Table Disclosures No relevant conflicts of interest to declare.

Real World Application of Thromboprophylaxis in Patients with Malignancy

Background: Cancer patients are at an increased risk for developing venous thromboembolism (VTE). Recent studies, such as the AVERT trial, have shown that primary prophylaxis (PPX) with direct oral anticoagulants (doacs) in high risk cancer patients (Khorana Risk Score (KRS) ≥2) appeared beneficial in preventing blood clots without marked increase in bleeding events (Carrier, et al 2019). However, widespread adoption of this strategy has not yet occurred, possibly due to concerns that the benefit may not be seen in "real life" patients. This study aims to determine, in a community and rural setting, whether the Khorana score predicts risk of VTE in ambulatory cancer patients who are initiating chemotherapy and to compare the absolute risk of VTE and bleeding with results from the AVERT study. Methods: We conducted a retrospective analysis of adult patients with hematologic or solid tumor malignancies (excluding multiple myeloma) starting a new course of chemotherapy between January 2016 and December 2018. Patients received their treatment at Gundersen Health System (GHS), an independent academic medical center in western Wisconsin, and data was abstracted from the electronic medical record. Patients on continuous anticoagulation were excluded. KRS was calculated for each patient based on individual values obtained prior to starting treatment. The medical record was reviewed for documentation of VTEs and bleeding events from the time of chemotherapy initiation through 180-days of treatment. Statistical analysis included the use of Chi-Square and Fisher's Exact tests, multivariate logistic regression and Kaplan-Meier analysis. Results: 1,025 patients were identified who fit the inclusion criteria. Demographics are shown in table 1, with comparisons to the AVERT study population. At the time of chemotherapy initiation, 35% (n=360) of our patients had a Khorana score of ≥2 and would have been eligible for PPX based on the AVERT study. 113 total patients received PPX per treating physician recommendation (int/high risk KRS n=45, low risk KRS n=68). Enoxaparin was most commonly used as prophylaxis (88%) while doacs were used in only 12.7%. Of those who did not receive prophylaxis, we found that KRS ≥2 was associated with significantly shorter VTE-free survival (graph 1). Patients in this group had 2.38-fold higher odds of developing a VTE compared to those with a score of 0-1 (p=.0012). In patients who received prophylaxis, the KRS was no longer predictive (p=0.87). In high risk patients without prophylaxis the probability of thrombosis within 180 days was 10%, nearly identical to that seen in the AVERT trial control arm (10.2%). Likewise, the bleeding event rate was similar at 2.4% compared to 1.8%. Of patients who received prophylaxis, the rates of bleeding (2.2 vs. 3.5%) and clotting (6.7 vs 4.2%) were also similar to the PPX arm of the AVERT study. Conclusions: In a community/rural setting, our population of cancer patients initiating chemotherapy showed a nearly identical risk of both VTE and bleeding as compared to the published clinical trial data. The KRS was able to predict the risk of VTE in our patients and stratify them into a higher risk subset, who may benefit from prophylaxis. In evaluating the patients for whom PPX was prescribed, it does not appear that the KRS was used in the decision-making process, as the majority who received PPX were in the low risk category. Given the published number needed to treat (17) and number needed to harm (100) with apixaban prophylaxis, widespread application of a prophylactic strategy to our patient population may have prevented 21 VTEs and led to 4 additional bleeding events. This risk to benefit ratio appears favorable. While this analysis does not consider important factors like patient preference, provider preference, and cost, it certainly does lessen concerns that our patients are significantly different from those that benefited from prophylaxis in the clinical trial. We plan on using this data to begin a KRS-based risk stratification approach to VTE prophylaxis in our cancer patients starting chemotherapy. Disclosures No relevant conflicts of interest to declare.

673 The Peripartum Risk of Deep Vein Thrombosis and Pulmonary Embolism in Women With Inflammatory Bowel Disease: A Population-Based Cohort Analysis

INTRODUCTION: Population-based adverse outcomes in the peripartum period are limited. Both Inflammatory Bowel Disease (IBD) and pregnancy are known risk factors for venous thromboembolism (VTE), encompassing deep vein thrombosis (DVT) and pulmonary embolism (PE). The aim of our study was to determine whether the odds of VTE are higher in women with Ulcerative Colitis (UC) and Crohn's disease (CD) at the time of delivery, compared to pregnant patients without IBD. METHODS: We performed a population-based retrospective cohort study using the Healthcare Cost and Utilization Project (HCUP)'s Nationwide Inpatient Sample (NIS) between 2005 and 2014. ICD-9-CM diagnosis and procedure codes were used to identify unique obstetric hospitalizations associated with delivery of an infant, and VTE. We created national estimates using appropriate weights for each NIS admission. Multivariable logistic regression was used to evaluate the association of UC and CD with VTE, while adjusting for age, race, smoking, obesity, Charlson Comorbidity Index, chronic steroid use, income, primary insurance, hospital region, and hospital bed size. RESULTS: The cohort comprised of 39.8 million deliveries, including 19,167 in women with UC and 31,083 in women with CD. Table 1 depicts baseline characteristics of the cohort. Overall, IBD patients were more likely to be white, have private insurance, receive care at larger hospitals, have a cesarean section and use chronic steroids compared to non-IBD patients. There were 19 (0.1%) cases of VTE in UC patients, 18 (0.06%) in CD patients versus 11,935 (0.03%) in non-IBD patients. Unadjusted odds ratios [OR] were 4.0 for UC; 95% confidence interval [CI] 1.5-10.5, and 2.5 (95% CI, 0.9-6.8) for CD. After adjusting for confounders, the OR for developing VTE was 1.63 (95% CI 0.41-6.55) among UC patients and 2.11 (95% CI, 0.79-5.64) in CD patients. As seen in Table 2, the following variables were associated independently with an increased risk for VTE: age, higher comorbidity scores, inpatient cesarean delivery, obesity and smoking. CONCLUSION: Our study showed that patients with IBD were not at greater risk for VTE at the time of delivery compared with non-IBD, perhaps due to the lower absolute risk of VTE over time (0.06-0.1% in our study vs 1.5-2.1% in the 2005 NIS database). Improved awareness and practices surrounding DVT prophylaxis may also be contributing. This study was not able to differentiate between active versus quiescent disease.