Length of hospital stay for treatment of deep venous thrombosis and the incidence of recurrent thromboembolism.

BACKGROUND Current guidelines suggest that all patients with acute deep venous thrombosis should be treated with intravenous heparin for at least 5 days, overlapping with warfarin sodium for 4 to 5 days. METHODS Using linked state of California hospital discharge records from 1991 to 1994 we identified patients with acute deep venous thrombosis without pulmonary embolism, and determined the 6-month cumulative incidence of rehospitalization for recurrent thromboembolism. Coding was validated by reviewing the charts of 218 patients matched with the statewide data from 4 local hospitals. RESULTS A total of 36924 linked records met study criteria. In the validation group, objectively confirmed thrombosis that was treated with intravenous heparin followed by warfarin was noted in 20%, 65%, 94%, and 95% of the patients who were hospitalized for 2 or fewer days or 3, 4, or 5 or more days, respectively. Statewide, among patients hospitalized for 3, 4, 5, and 6 days, the 6-month cumulative incidence of hospitalization for recurrent thromboembolism was 5.4%, 5.1%, 5.4%, and 6.0%, respectively. Multivariate modeling of patients hospitalized for 3 to 10 days revealed that recurrent thromboembolism was associated with the length of hospitalization (odds ratio [OR], 1.06 each additional day; 95% confidence interval [CI], 1.04-1.08), presence of malignancy (OR, 1.58; 95% CI, 1.46-1.68), age (OR, 0.85 each 10 years; 95% CI, 0.84-0.86), dementia (OR, 0.38; 95% CI, 0.26-0.49), hospitalization for multiple injuries within 3 months (OR, 0.46; 95% CI, 0.32-0.60), and surgery within 3 months (OR, 0.84; 95% CI, 0.78-0.90). CONCLUSIONS We found no evidence that a stay of 4 days for treatment of deep venous thrombosis was associated with a higher rate of recurrent thromboembolism compared with hospitalization for 5 or more days. Although the evidence was not as strong, the incidence of recurrent thromboembolism after a stay of 3 days appeared comparable with that after a stay of 5 days. These findings suggest that fewer than 5 days of intravenous heparin overlapping with warfarin may provide effective initial treatment for deep venous thrombosis among patients deemed ready for hospital discharge.