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

Importance: 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. Objectives: To assess the risk of VTE among outpatients with COVID-19 and identify independent predictors of VTE. Design, Setting, and Participants: 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. Exposures: Patient demographic and clinical characteristics identified from integrated electronic health records. Main Outcomes and Measures: 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. Results: 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]). Conclusions and Relevance: 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.

Health-related quality of life associated with warfarin and direct oral anticoagulants in venous thromboembolism.

INTRODUCTION: Venous thromboembolism (VTE) is commonly treated with oral anticoagulants, including warfarin or direct oral anticoagulants (DOACs). Although DOACs are associated with favorable treatment satisfaction, few studies have assessed whether quality of life differs between DOAC and warfarin users. MATERIALS AND METHODS: We invited adults enrolled in two California-based integrated health care delivery systems and with a history of VTE between January 1, 2015 and June 30, 2018 to complete a survey on their experience with anticoagulants. Health-related quality of life (QOL) was assessed using the RAND 36-item Short Form Health Survey (SF-36), which measures QOL in 2 general component scores (physical and mental). We used multivariable linear regression to compare mean QOL component scores between DOAC-users and warfarin-users, adjusting for patient and clinical characteristics. RESULTS: Overall, 2230 patients (43.1 % women and 31.8 % >75 years of age) taking anticoagulants answered at least 1 question on the SF-36, 975 taking DOACs and 1255 taking warfarin. After adjustment for patient-level factors, there were no significant differences in either physical component scores (39.2 v 38.3, p = 0.24) or mental component scores (48.5 v 49.0, p = 0.42) between DOAC and warfarin users. CONCLUSIONS: Health-related QOL did not significantly differ between DOAC and warfarin users with a history of VTE.