Primary versus Secondary DVT: Clinical Spectrum and Outcomes

Peter Henke, MD, Eric Ferguson, MD, Susan Blackburn, RN, Mary Proctor, RN, Manu Varma, C. Barry Deatrick, MD, Gilbert Upchurch, MD, Thomas Wakefield, MD and Derek Woodrum, MD
University of Michigan, Ann Arbor, MI

Objective: Although the treatment for acute DVT (deep vein thrombosis) is uniform, the circumstances under which they develop vary widely and may impact outcomes. This study compared clinical features and outcomes in patients who developed DVT while hospitalized to patients with primary DVT.
Methods: Consecutive patients without a history of DVT or pulmonary embolism (PE) from 2000-02 were abstracted for demographics, risk factors, DVT anatomical characteristics, treatment, and outcomes of death and new PE. Comparison between hospitalized patients with DVT (Inpt) and those presenting with DVT (Outpt; no identified surgery or trauma admissions within 30 days) was done by univariate and multivariate statistics. Surveys were mailed to all living patients to assess long term sequela.
Results: A total of 293 patients with a mean age of 55 years and 49% men had confirmed DVT by objective means (92% duplex) with a follow-up of 25±21 months. Comparison of Outpt and Inpt groups in shown in the Table.

Factor	Outpt (N = 196)	Inpt (N = 97)	P
Medical illness	12%	17%	.02
Malignancy	32%	20%	.02
Surgery or trauma	22%	77%	<.01
Bilateral DVT	4%	11%	.02
Tibioperoneal DVT	71%	60%	.06
LMWH	79%	45%	<.01
Coumadin	81%	64%	<.01
New PE	10%	21%	.01
Death	15%	15%	.97

By survey (21% response), Outpts were more likely than Inpts to develop varicosities and have daily frustration related to their legs (P <.05), but no difference in edema or ulceration. Considering the entire group, independent factors associated with freedom from PE included ambulation (OR=2.3; 95% CI=1.1-5.0; P = .04), while bilateral DVT (OR=.26; 95% CI=.09-.76; P = .013) was associated with greater risk. Independent factors associated with survival included ambulation (OR =3.0; 95%CI=1.3-7.2; P=.02), coumadin use (OR=2.7; 95%CI=1.2-6.1; P=.015), and tibioperoneal DVT (OR=2.4; 95%CI=1.1-5.5; P=.03) while malignancy (OR=.1; 95%CI=.05-.24; P<.01), myocardial infarction (OR=.12; 95%CI=.01-.92; P=.04) were associated with lower survival.
Conclusion: Patients who develop DVT as a consequence of inpatient hospitalization generally have more extensive DVT, an increased risk of PE, less long term morbidity, but no difference in long-term mortality as compared to outpatients presenting with DVT.