Adoption of Outpatient Treatment of Deep Vein Thrombosis in the U.S.: The Reasons for Geographic and Racial Differences in Stroke Study (REGARDS)
Authors: Zakai Neil A , McClure Leslie A , Lutsey Pamela L , Folsom Aaron R , Cushman Mary 
Published: October 2019

Abstract

Introduction: Outpatient treatment of deep vein thrombosis (DVT) has been shown equivalent to inpatient treatment in clinical trials and results in cost savings and increased patient-convenience. Despite the advantages, there are few studies on the national uptake of outpatient care of DVT in the U.S. and there are no national surveillance studies of DVT. Through understanding the current treatment patterns of DVT, we can design interventions to reduce health care costs and increase patient convenience.
Methods: Between 2003-07, 30,239 participants ≥45 years old were enrolled in REGARDS, a nationally representative cohort recruited from the contiguous U.S. By design, 55% were female, 41% were black, and 56% lived in the southeast. Venous thrombosis (VTE) events were ascertained through 2011, with identification by telephone interview, review of reported hospitalizations, and review of deaths and validated by physician review of hospital and outpatient records. Using all available information, characteristics of the VTE event and treatment were systematically recorded. Location of residence was defined by geocoding of the address with urbanicity defined by census tract, and other risk factors were obtained through surveys, telephone interviews, or an in-home visit. We used logistic regression to determine the predictors of outpatient treatment of DVT among those with DVT.
Results: Over 5 years of follow-up 379 VTE events occurred (incident and recurrent); 185 were diagnosed with a pulmonary embolism and 53 occurred as a complication of hospitalization (and not eligible for outpatient treatment) leaving 141 DVT events potentially eligible for outpatient treatment. Only 28% of DVT events (39 of 141) were treated as an outpatient. Factors significantly associated with being treated as an outpatient include younger age, female sex, white race, later year of DVT diagnosis, and living in an urban area (Table). Other risk factors with high odds ratios that were not statistically significant were living outside the southeast of the U.S. and being a high school graduate (Table).
Conclusions: In a contemporary, nationally representative cohort, only 28% of DVT events were treated as an outpatient. Adverse socioeconomic status, residence in a rural area, advancing age, race, and male sex were independently associated with lower likelihood of outpatient treatment. These data highlight the low proportion of DVTs currently treated on an outpatient basis, as well as disparities in the outpatient treatment of DVT. Outpatient DVT treatment has the potential to reduce the cost of medical care for DVT in the U.S.
Table: Predictors of Outpatient treatment of DVTs in the REGARDS Study Variable Prevalence of Factor (%, n) Odds of Outpatient Treatment* Age (per 10 years younger) 69 years (Median) 1.90 (1.19, 3.02) Year of VTE (per 1 year later) 2008 (Median, range 2003-11) 1.35 (1.03, 1.77) Sex (female vs male) 46.8% (66) 2.41 (1.06, 5.47) Race (white vs black) 66.0% (93) 3.29 (1.30, 8.30) Region (elsewhere vs southeast) 50.4% (71) 2.00 (0.87, 4.63) High School Graduate (yes vs no) 90.8% (128) 4.51 (0.52, 38.82) Income >$20,000 (yes vs no) 63.8% (90) 2.63 (0.87, 7.94) Living in a Urban Area (yes vs no) 75.2% (106) 4.16 (1.25, 13.79) Adjusted for age, sex, race, VTE event year and region*

Disclosures
No relevant conflicts of interest to declare.