Hospital-Aquired Venous Thromboembolism Risks: Comparing In-Hospital and Post-Discharge Events

Background: Venous thromboembolism (VTE) is considered the most common preventable hospital complication and VTE prophylaxis rates are benchmarks of hospital quality. Hospital-acquired VTE (HA-VTE) is defined as VTE that occurs during hospitalization or within 90 days of discharge. Recent studies, however, have shown that higher VTE prophylaxis rates in hospitalized medical patients do not correlate with a decrease in HA-VTE. Targeting high risk patients may be appropriate. To improve understanding of HA-VTE at our institution, we set out to determine HA-VTE incidence in medicine patients and associated risks.

Methods: We identified all adult patients hospitalized on a general medicine service at an urban tertiary academic medical center between 1/1/2013-6/30/14 diagnosed with deep vein thrombosis (DVT) or pulmonary embolism (PE) during hospitalization or within 90 days of discharge. Data were gathered electronically using a VTE Abstraction Tool (J Hosp Med 2014) and from chart abstraction. Prophylaxis was “appropriate” if administered in accordance with an institutional guideline. Padua prediction scores were calculated to describe VTE risk.

Results: Over 18 months, 27 patients were diagnosed with VTE, representing <0.5% of all medical admissions. Sixteen (59%) were diagnosed during hospitalization; 11 (41%) after discharge. Eight (30%) were diagnosed with PE (4 in-hospital; 4 after discharge); 20 (74%) with DVT (12 in-hospital; 8 after discharge). Mean age was 53; 74% were men. (Table 1) The vast majority received appropriate prophylaxis in hospital; none were discharged on prophylaxis. Patients with in-hospital VTE had longer lengths of stay and higher critical illness rates. They were more likely to be considered “high risk” with Padua Prediction Scores ≥4 versus those with post-discharge VTE. Of patients with HA-VTE, acute infection (74%), heart and/or respiratory failure (63%) and reduced mobility (41%) were the most frequently observed risks.

Conclusions: HA-VTE remains rare in medicine patients. The risk profiles of patients with in-hospital versus post-discharge VTE differ. Additional research is needed to determine which medical patients are at highest risk for HA-VTE and when prophylaxis is appropriate.