Incidence of proximal deep vein thrombosis in medical critical care patients

BACKGROUND: Approximately 13-31% of medical critical care patients develop deep vein thrombosis (DVT). However, there are very few reports regarding the incidence of DVT among Asian patients without routine prophylaxis. The objectives of this study were to assess the prevalence and incidence proportion of proximal DVT in Thai medical critical care patients not receiving thrombosis prophylaxis. METHODS: We conducted a prospective cohort study in medical critical care patients admitted to Siriraj Hospital, Thailand between November 2008 and November 2009. Patients were screened for proximal DVT by duplex ultrasonography performed 48 h, 7, 14 and 28 days after admission. Primary outcomes were prevalence and incidence proportion of DVT. Factors associated with the development of proximal DVT were evaluated by multivariate analysis. RESULTS: Of the 158 patients enrolled in the study, 25 had proximal DVT (15.8%). Nine patients (5.7%) had DVT on the first test at 48 h, while 10 (6.3%), 2 (1.3%) and 4 (2.5%) patients had developed DVT on days 7, 14, and 28, respectively. Thus, the prevalence at the beginning of the study was 5.7% (95%CI 2.6-10.5) and the incidence proportion was 10.1% (95%CI 5.9-15.9). The multivariate analysis showed that age (odds ratio [OR] per 1-year increase was 1.04, 95% confidence interval [CI] 1.01-1.07), female gender (OR 4.05, 95%CI 1.51-12.03), femoral venous catheter (OR 11.18, 95%CI 3.19-44.83), and the absence of platelet transfusion (OR 0.07, 95%CI 0.003-0.43) were associated with the development of proximal DVT. Patients with proximal DVT had a longer hospital length of stay (22 days [IQR 11-60] vs. 14 days [7-23], p = 0.03) and spent more time on mechanical ventilation (10 days (3.3-57) vs. 6 days (3-12), p = 0.053) than patients without DVT. Patient mortality was not affected by the presence of DVT (52% vs. 38.3%, p = 0.29). CONCLUSIONS: Routine thromboprophylaxis is not used in our institution and the prevalence and incidence proportion of proximal DVT in Asian medical critical care patients were both substantial. Patients with older age, female gender, an intravenous femoral catheter, and the absence of platelet transfusion all had a higher chance of developing proximal DVT.