[Outpatient treatment of deep vein thrombosis: comparative study with historical inpatients]

Outpatient treatment of deep venous thrombosis (DVT) has been proposed as a safe and cost-saving process, either as a mixed pattern: as an inpatient for 1 to 3 days followed by outpatient treatment; or rarely as completely outpatient.

We evaluated two cohorts of consecutive patients diagnosed with DVT. Patients who received entirely outpatient treatment in the years 2003 and 2004, compared with historical patients treated as inpatients during the year 2002. Our aim was to evaluate safety and the days of stay saved because of outpatient treatment of DVT.

A total of 293 patients entered the study (Inpatients, 109; outpatients, 184). Demographic and clinical characteristics of patients were similar. Mean time of anticoagulant therapy and follow up were also both similar in the two groups. Major haemorrhage rate was 8% (CI 95% 4-15) in patients treated in hospital and 3% (CI 95%1-6.57) [Relative Risk (RR) 0.38] in patients treated as outpatients. Complications of venous thromboembolic disease occurred in 4% (CI 95% 1.18-9.68) of hospitalised patients and 5% (CI 95% 2.41-9.37) (RR 1.25) of patients treated as outpatients. The death rate was 11% (CI 95% 6-18.8) in hospitalised patients and 4% (CI 95% 1.68-7.99) (RR 0.36) in patients treated as outpatients. We observed a reduction of hospitalisation in relation to the index-year of 72.5% for the year 2003 (CI 95% -0.08 to -0.04) and 79% for the year 2004 (CI 95% -0.08 to -0.05) (p<0.001). Overall, 844 days of unnecessary hospitalisation were saved.

Complete outpatient treatment of DVT shows outcomes at least as safe as inpatient treatment, adding additional reductions in costs for the Health System.