Risk Factors Associated with Venous Thromboembolic Events in Patients with Malignancy.

Abstract

Malignancy is a major risk factor for venous thromboembolic events (VTE), but not all patients with malignancy develop this complication. Who best to aggressively prophylax is thus not well defined. In the current study, 960 consecutive patients, 523 men and 437 women, admitted to the University of Michigan with malignancy between 1992–2000 were identified using ICD-9CM codes. Factors including cancer stage, type, therapy, and patient vital status were obtained from a database maintained prospectively by the University of Michigan Cancer Registry as well as a review of the medical record. Acute VTE, confirmed on radiological or ultrasound studies, occurred in 408 patients and were compared to 552 patients who did not experience any VTE using logistic regression analysis. Factors associated with VTE include solid tumors (Odds Ratio 5.0; 95% confidence interval 1.65–14.9, P =.004), infection (4.9; 1.2–19.8, P =.025), and advanced age (1.05; 1.03–1.08, P <.001). Interestingly, while leukopenia (4.2; 1.23–14.6, P =.023) was associated with an increased incidence of VTE, neutropenia was not, suggesting that a deficiency of a different class of leukocytes is more important in predisposing to primary VTE. Neutropenia was associated with recurrent, but not primary VTE (P =.034). Type of therapy, gender, and stage were not associated with VTE. Kaplan Meier estimated survival was decreased in patients with VTE as compared to those without (3.3 vs. 3.7 years, P=.18). Factors associated with a decreased survival include solid tumors (3.9; 1.8–8.4, P <.01), infection (3.3; 1.1–9.9, P =.03), advanced stage (1.6; 1.2–2.1, P <.01), and increased age (1.02; 1.0–1.04, P =.01). Patients with solid tumors, advanced age, and leukopenia have a significantly increased risk of VTE and might benefit from aggressive VTE prophylaxis, whereas other patients with malignancy can probably be carefully observed.