Venous thromboembolism in medical patients during hospitalisation and 3 months after hospitalisation: a prospective observational study

OBJECTIVES This study was conducted to assess the incidence and risk factors for venous thromboembolism (VTE) in a cohort of medical patients both during the period of hospitalisation and following discharge. DESIGN This was a prospective observational study to document the risk profile and incidence of VTE posthospitalisation among all medical patients admitted to our institution during the trial period. SETTINGS Primary healthcare. Single tertiary referral centre, Tasmania, Australia. PARTICIPANTS A total of 986 patients admitted to the medical ward between January 2012 and September 2012 were included in the study with male to female ratio of 497:489. The mean age of patients was 68 years (range 17-112, SD 16). RESULTS Overall, 54/986 patients (5.5%) had a VTE during the study period. Of these, 40/54 (74.1%) occurred during hospitalisation and 14/54 (25.9%) occurred following discharge. VTE risk factors revealed in multivariate analysis to be associated with a previous diagnosis of VTE (p<0.001, OR=6.63, 95% CI 3.3 to 13.36), the occurrence of surgery within the past 30 days (p<0.001, OR=2.52, 95% CI 1.33 to 4.79) and an admission diagnosis of pulmonary disease (p<0.01, OR 3.61, 95% CI 1.49 to 8.76). Mobility within 24 hours of admission was not associated with an increased risk. There was risk of VTE when the length of stay prolonged (p=0.046, OR=1.01, 95% CI 1.00 to 1.03), however it was not sustained with multivariate modelling. VTE-specific prophylaxis was used in 53% of the studied patients. Anticoagulation including antiplatelet agents were administered in 63% of patients who developed VTE. CONCLUSIONS This prospective observational study found that 5.5% of the studied patients developed VTE. Among those, 25.9% (14/54) of patients had a detected VTE posthospitalisation with this risk being increased if there was a history of VTE, recent surgery and pulmonary conditions. Thromboprophylaxis may be worth considering in these cohorts. Further study to confirm these findings are warranted. TRIAL REGISTRATION NUMBER ACTRN12611001255976.