Clinical trials have demonstrated the efficacy of anti-thrombotic prophylaxis in preventing venous thromboembolic events (VTE). However, its effectiveness outside of the clinical trials setting is less well known. This study explored VTEs occurring during hospital admissions stratified by prophylactic regimen in order to understand the effectiveness of thromboprophylaxis in current community practice.
Using a large, geographically diverse, multi-hospital US database, we identified hospitalized patients aged ≥40 years with hospital stays ≥6 days, at risk of VTE medical conditions including respiratory disorders, circulatory disorders, infectious diseases, and neoplasm during calendar years 2001-2003. We examined whether patients received thromboprophylaxis within the first 2 days of admission and compared rates of VTEs identified by ICD-9-CM diagnosis codes during the admission by type of prophylaxis and condition using chi-square. Duration of prophylactic regimen was also determined.
Of 10,142 eligible subjects, 2,588 (25.5%) had respiratory disorders, 3,855 (38%) had circulatory disorders, 969 (9.5%) had infectious diseases and 2,730 (27%) had neoplasms. Mean length of stay was 9.9 days. Overall VTEs rate was 9.4% and was higher among patients with circulatory disorders (15.5%) followed by neoplasms (7%), infectious diseases (5.4%), and respiratory disorders (4.5%). Only 2,447 patients (24%) received thromboprophylaxis with low-molecular-weight heparin (LMWH) or unfractionated heparin with a mean treatment length of 5.8 days. VTEs rates were significantly higher among patients receiving no prophylaxis compared to subjects receiving thromboprophylaxis (9.9% vs 7.9%, respectively, OR=0.8, 95% CI: 0.68-0.93, P=.003) (Table 1). The lowest rate was seen in LMWH group (7.0%, P<.05 compared to “no prophylaxis”). This risk reduction remains significant among patients with infectious diseases (2.4% vs 6.2%, P=.03) or respiratory disorders (2.4% vs 5.1%, P<.01) (Table 2).
This study demonstrates the effectiveness of anti-thrombotic prophylaxis in a large, real-world database and shows that VTEs occurred frequently, especially among medical patients receiving no prophylaxis, and that rates varied by condition.
Using anti-thrombotic prophylaxis in a non-trial community setting has significant impact on reducing VTEs among medical patients at risk for VTE.Table 1—
Numbers and rates of VTEs occurring during hospital admissions by prophylactic regimen administered and duration of prophylaxisType of anticoagulantsIn-hospital eventsDuration of prophylactic regimen (days)NFrequency%MeanSDNo prophylaxis7,6957639.9--UFH1,9191568.1†5.84.8LMWH528377.0†5.84.5Total10,1429569.4--
LMWH = low-molecular-weight heparin; UFH = unfractionated heparin.Table 2—
Numbers and rates of VTEs occurring during hospital admissions by clinical condition and prophylaxis statusAt-risk medical conditionsNo ProphylaxisReceived ProphylaxisP valueNFrequency%NFrequency%Circulatory disorders2,87846016.097713613.9.1233Neoplasm2,0161537.6714395.5.0561Infectious diseases761476.220852.4.0324Respiratory disorders2,0401035.1548132.4.0072Total7,6957639.92,4471937.9.003
Michelle Dylan, Grant monies (from industry related sources) Cerner Health Insights received research grants from Sanofi-Aventis.