Validation of the Khorana Venous Thromboembolism Risk Score in Japanese Cancer Patients

Background: Although the Khorana venous thromboembolism (VTE) risk score (KRS) is well recognized as a simple VTE risk assessment method in patients with cancer, whether it is suitable for Asian populations is unclear. Objectives: This study validated KRS for the prediction of VTE and investigated the value of the KRS in predicting mortality in Japanese patients with cancer. Methods: A body mass index value of 25 kg/m2 or more was defined as obesity according to World Health Organization consensus. A total of 27,687 patients with cancer were subdivided into low- (0), intermediate- (1-2), and high-score (3) groups by the KRS. The primary and secondary endpoints were VTE and all-cause mortality, respectively. Results: The prevalence of VTE was 1.7%, 7.3%, and 11.0% for low-, intermediate-, and high-score patients, respectively. Receiver operating characteristic (ROC) analysis showed that the KRS significantly predicted VTE (area under the curve, 0.679; 95% confidence interval [CI] 0.666-0.692; P < 0.001). The cutoff value for the KRS was 1.0. Logistic regression analysis demonstrated that the KRS was an independent predictor of VTE (odds ratio 1.766; 95% CI 1.673-1.865; P < 0.01). The cutoff value of the KRS for all-cause mortality determined by ROC analysis was 2.0. Kaplan–Meier analysis demonstrated a significantly higher incidence of mortality in the KRS ≥2 group than in the KRS 0-1 group (log-rank: P < 0.01). Conclusions: The KRS was useful in Japanese patients with cancer and might be a potentially useful marker for the prediction of mortality. Establishing optimal scores for Japanese subjects is mandatory because of its low diagnostic ability. (KUMAMON Cancer registry; UMIN000047554)