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This study examined warfarin therapy discontinuation and its risk factors among patients with unprovoked venous thromboembolism (VTE) in the US clinical practice setting. Adult patients with unprovoked VTE were identified from the MarketScan claims database from January 1, 2006 to December 31, 2012. The index date was defined as the date of first VTE diagnosis. Patients were required to have no VTE diagnosis in the 6 months before index date and continuous health plan enrollment for 6 months before and 12 months after the index date. Warfarin discontinuation rates and adjusted hazard ratios (HRs) were reported. Of 21,163 eligible patients, 15,463 were diagnosed with deep vein thrombosis (DVT) only (73.1%), 5027 with pulmonary embolism (PE) only (23.7%), and 673 with DVT and PE (3.2%). The average duration of warfarin therapy was 5.2 months (SD = 3.0). During 1-year follow-up, 21.4% patients discontinued therapy within 3 months, 42.8% within 6 months, and 70.1% within 12 months. PE versus DVT [HR = 0.77, 95% confidence interval (CI) = 0.74-0.80], comorbid atrial fibrillation (HR = 0.73, 95% CI = 0.66-0.81), thrombophilia (HR = 0.62, 95% CI = 0.54-0.71), and age >40 years (41-65 years: HR = 0.86, 95% CI = 0.81-0.91; >65 years: HR = 0.82, 95% CI = 0.77-0.87) were significantly associated with reduced risk of warfarin discontinuation. Alcohol abuse/dependence (HR = 1.36, 95% CI = 1.20-1.55), cancer history (HR = 1.13, 95% CI = 1.07-1.19), bleeding (HR = 1.07, 95% CI = 1.01-1.15), and catheter ablation (HR = 1.10, 95% CI = 1.00-1.20) in the 6 months before index date were significantly associated with increased risk for warfarin discontinuation. In conclusion, nearly 1 of 4 patients with unprovoked VTE discontinued warfarin within 3 months. Three of 4 patients discontinued therapy within 1 year. Younger age and multiple clinical factors are associated with warfarin therapy discontinuation.

Patients hospitalized with acute medical illness have an elevated risk of venous thromboembolism (VTE). American College of Chest Physicians guidelines list various chronic illnesses, sepsis, advanced age, history of VTE, and immobility as risk factors and recommend prophylactic anticoagulation using fondaparinux, low-molecular weight heparin, or low-dose unfractionated heparin. The objectives of this study were to examine pharmacological prophylaxis against VTE among hospitalized medically ill patients and to assess demographic and clinical correlates related to VTE prophylaxis. A retrospective (1999-2010) electronic medical records study included patients aged 40 years and older hospitalized for at least 3 days, with significant medical illness or with a VTE hospitalization 30-365 days before admission. Each patient's first qualifying hospitalization was analyzed. Exclusions were if VTE treatment was started within 1 day of admission, or if warfarin (and not heparin or enoxaparin) was used. Prophylaxis was defined if the first inpatient dose of subcutaneous heparin or enoxaparin was at prophylaxis levels (lower than treatment levels). Multivariable logistic regression was used to examine factors associated with VTE prophylaxis. Among 12,980 patients, 22.1% received prophylaxis (11.8% with enoxaparin, 10.3% with heparin). VTE prophylaxis was positively associated with year of hospitalization, subcutaneous heparin in the month before admission, aspirin, self-pay status, age, and sepsis. VTE prophylaxis was negatively associated with smoking, alcohol, warfarin in the past 30 days, and primary diagnoses of stroke, infectious disease, or inflammatory bowel disease. Pharmacological VTE prophylaxis has increased significantly over the past 12 years but is still largely underused in patients hospitalized with acute medical illness. Multiple demographic, behavioral, and clinical factors are associated with inpatient VTE prophylaxis.

Patients who have total hip (THR) or knee (TKR) replacement have an elevated risk of venous thromboembolism (VTE). The American College of Chest Physicians guidelines recommend prophylactic anticoagulation. The aim of the study was to examine pharmacologic prophylaxis against VTE among patients with THR or TKR and to assess demographic and clinical correlates related to VTE prophylaxis. Using 15 years of data (1995-2009) from an electronic medical record system for an inner-city public hospital in the United States, we examined pharmacologic prophylaxis against VTE and associated factors in patients after THR (n = 242) and TKR (n = 317). Before the early 2000s, aspirin was the most common prophylaxis agent (THR, 61% and TKR, 65%), and 26% of patients with THR and 19% of patients with TKR did not receive prophylaxis. Enoxaparin use has increased since 2000, and warfarin is now the most common prophylaxis agent (THR, 70% and TKR, 61%). After controlling for time period, factors associated with prophylaxis pattern included obesity, hip fracture, and the surgeon's number of years in practice. VTE prophylaxis medications in patients with total joint replacement have changed over 15 years, in trends generally consistent with the evolution of guidelines. Obesity, history of hip fracture, and physician's experience are associated with the prescription of VTE prophylaxis medications.

Vitamin K antagonist (VKA) and aspirin (ASA) are recommended for stroke prevention in patients with atrial fibrillation (AF). This study examined VKA and ASA use and their clinical correlates, including CHADS2 stroke risk scores, among adult patients with AF in the general population. Participants included 1290 (1.72%) adults reporting diagnosis with AF (mean age, 64.9 years; 65% men) from the 2009 US National Health and Wellness Survey, an online, self-administered, nationwide, stratified random sample survey of 75,000 adults. Antithrombotic use patterns, including VKA, ASA, VKA+ASA, and non-VKA/ASA, and their correlates were examined using logistic regressions. Respondents with AF were treated with VKA (26.6%), ASA (34.5%), VKA+ASA (15.4%), or neither (23.5%). Among those with CHADS2 ≥1, 19.3% did not report use of VKA or ASA. Among those with CHADS2 ≥2, 35.7% were treated only with ASA. Adjusting for covariates in logistic regressions, CHADS2 ≥1 was associated with VKA and/or ASA (vs. non-VKA/ASA) use (P ≤ 0.02), but CHADS2 score did not differentiate VKA versus ASA use (P > 0.4). Comorbidities were associated with ASA versus VKA use (P ≤ 0.01). Older age, male gender, married status, and obesity were each associated with use of at least one of the treatments investigated (all P < 0.05). One-in-five AF patients with CHADS2 ≥1 were untreated and more than one-third with CHADS2 ≥2 treated with only ASA for stroke prevention. Our findings suggest that although patient characteristics including CHADS2 score were associated with either VKA or ASA use, CHADS2 score was unrelated to VKA versus ASA treatment.

The objective of this study was to examine venous thromboembolism (VTE) prophylaxis use, risk reduction, and readmission in medically ill patients during hospitalization and after discharge. This 5-year retrospective study linked outpatient files from MarketScan Commercial and Medicare Supplemental databases. Patients were categorized into prophylaxis and non-prophylaxis groups based on guideline-recommended anticoagulant use from the index date to 180 days posthospital discharge and before the first VTE event date. Outcome variables were VTE events and rehospitalization. Risk adjustment was conducted within the prophylaxis group and between the prophylaxis and non-prophylaxis groups using propensity score matching. Among 4467 patients, 28.99% of the patients (n = 1295) were admitted with cancer, 18.03% (n = 805) with pneumonia, 14.06% (n = 628) with heart failure, 11.06% (n = 494) with stroke, 11.11% (n = 496) with sepsis, 8.08% (n = 361) with infectious diseases, 5.6% (n = 250) with severe respiratory disorders, 1.81% (n = 81) with inflammatory bowel disease, 1.05% (n = 47) with obesity, 0.20% (n = 9) with neurologic disorders, and 0.02% (n = 1) with acute rheumatic fever. Among those with 180-day continuous enrollment after the index date (n = 3511), 51.81% (n = 1819) received anticoagulant therapy only, 2.48% (n = 87) received mechanical compression treatment only (stocking or pneumatic compression), and 4.41% (n = 155) received both during hospitalization. Anticoagulant therapy rates ranged from 88.64% (obesity) to 32.39% (inflammatory bowel disease). Among anticoagulant therapy patients, 740 patients (40.68%) received low-molecular weight heparin only and 806 patients (44.31%) received unfractionated heparin. After risk adjustment, compared with patients without VTE prophylaxis, anticoagulant prophylaxis patients had lower VTE (3.62% vs. 4.27%, P < 0.04) and readmission rates (24.22% vs. 27.95%, P < 0.02) during the 6 months post-index hospital admission. In conclusion anticoagulant prophylaxis is underutilized and is associated with reduced VTE risk and a decrease in rehospitalizations for medically ill patients.