Risk Stratification for the Development of Venous Thromboembolism in Hospitalized Patients with Cancer

Abstract

Introduction: No method of venous thromboembolism (VTE) risk stratification exists for hospitalized cancer patients. The Khorana score is a validated tool in outpatients with cancer. The objective of this study was to assess the Khorana score for predicting development of VTE in cancer patients during admission to hospital. Methods: We conducted a retrospective analysis of data collected from healthcare records of consecutive, medically-ill cancer patients hospitalized between January and June 2010 in 3 academic medical centers in Canada. Objectively diagnosed symptomatic VTE during hospitalization, anticoagulant thromboprophylaxis (TP), and Khorana score variables were collected for every patient. Patients receiving therapeutic anticoagulation at admission, and those with incomplete data were excluded. The risk of VTE based on Khorana score category was evaluated using logistic regression. Continuous data were compared using a Student's t-test and expressed using the means and standard deviations. Categorical data were compared using the Pearson Chi-square test and were expressed as percentages. Statistical significance was defined as alpha less than 0.05. Results: 1398 patients were included. Mean age was 61.6 years, 51.2% were male, and mean BMI was 25.9 kg/m2. The most frequent tumor types were non-small cell lung carcinoma (12.7%) followed by lymphoma (10.9%). The median length of stay was 6 days (range 0-114 days). The most frequent reasons for hospitalization were chemotherapy (22.3%) followed by pain and palliation (21.4%). 34.5% received anticoagulant TP (n = 483/1398). The incidence of VTE was 2.9% (41/1398) overall, 5.4% (9/166) in high, 3.2% (26/817) in moderate, and 1.4% (6/415) in low Khorana score risk groups. High risk patients were significantly more likely than low risk patients to have VTE (p=0.016; OR 3.9, 95% CI 1.4-11.2). There was no difference in VTE incidence between patients who received anticoagulant TP and those who did not (3.5% vs 2.6%, p = 0.345). Patients with high risk Khorana score were more likely to receive anticoagulant TP than those with low risk Khorana score (46.4% vs. 23.9%, p <0.001, OR 2.8, 95% CI 1.9-4.0). Total incidence of major bleeding was 1.8% (25/1398). There was no difference in major bleeding between patients who received anticoagulant TP and those who did not (1.7% vs. 1.9%, p = 0.787). Conclusion: The Khorana score is predictive of VTE development in cancer patients who are hospitalized for medical illness and may be a useful tool for tailoring inpatient anticoagulant prophylaxis. Disclosures Lee: LEO: Consultancy, Honoraria; Bayer: Consultancy, Honoraria; Bristol Myers-Squibb: Consultancy, Honoraria, Research Funding; Pfizer: Consultancy, Honoraria. Carrier:BMS: Research Funding; Leo Pharma: Research Funding. Wu:Pfizer: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Leo Pharma: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau.

The risk of venous thromboembolism in cancer patients receiving chemotherapy: a meta-analysis with systematic review

“…Due to direct effects on vascular endothelium (2), there is a 6-to 7-fold risk of cancer-associated VTE observed in patients treated with chemotherapy (3). Regardless, few cancer patients receive thromboprophylaxis during chemotherapy (4).…”

Prediction and Prevention of Cancer-Associated Thromboembolism

“…It relies on five simple clinical and laboratory variables including type of cancer, components of the complete blood count, and body mass index (Table 1) [9]. Recent re-evaluations of the score suggest that the cutoff for high-risk VTE-set in the original publication as a score of 3 or higher-may be more optimally defined as a score of 2 or higher in both outpatients and hospitalized patients with cancer [10][11][12]. In particular, the first prospective validation of this score, led by the Vienna group, found a nearly 10% cumulative 6-month incidence of VTE in patients with a score of 2 [10].…”

“…There are some predictive risk tools that have been studied in this population, but none have been specifically designed for inpatients with cancer. Two retrospective cohort studies have established that a Khorana score of ≥2 is predictive of inpatient VTE as well [12,38]. Although inpatient thromboprophylaxis is widely recommended by guidelines and is a quality metric for regulatory agencies, there are scant data to support its use.…”

Cancer associated thrombosis and mortality in patients with cancer stratified by khorana score risk levels

“…[4][5][6][7] The risk of VTE varies widely among cancer patients. 8 The Khorana score (KS) is an externally validated risk prediction clinical algorithm [9][10][11][12][13][14][15][16][17][18][19][20][21][22][23] to assess the risk of VTE in patients with cancer. This score uses multiple independent predictors, including the tumor's primary site, pre-chemotherapy platelet count, hemoglobin levels < 100 g/L or use of red blood cell growth factors, pre-chemotherapy leucocyte count > 11 x 10 9 /L, and body mass index (BMI) ≥ 35 kg/ m 2 .…”