External validation of a novel electronic risk score for cancer‐associated thrombosis in a comprehensive cancer center

Abstract

AbstractVenous thromboembolism (VTE) is a significant complication for cancer patients undergoing systemic therapy. We performed an independent external validation for a recently derived and validated a novel electronic health record (EHR) VTE risk score in a comprehensive cancer center. Adult patients with incident cancer diagnoses were identified from MD Anderson Cancer Center Tumor Registry 1/2017–1/2021. Baseline covariates extracted at the time of first‐line systemic therapy included demographics, cancer site/histology, stage, treatment, complete blood count, body mass index, recent prolonged hospitalization, and history of VTE or paralysis. VTE was ascertained using an institution‐specific natural language processing radiology algorithm (positive predictive value of 94.8%). The median follow‐up for 21 142 cancer patients was 8.1 months. There were 1067 (5.7%) VTE within 6 months after systemic therapy. The distribution of the novel score for 0‐, 1, 2, 3, 4, 5+ was 5661, 3558, 3462, 3489, 2918, and 2054; while the corresponding 6‐month VTE incidence was 1.3%, 3.1%, 5.4%, 7.3%, 9.3%, and 13.8%, respectively (c statistic 0.71 [95% CI 0.69–0.72] with excellent calibration). In comparison, the Khorana score had a c statistic of 0.64 [95% CI 0.62–0.65]. The two risk scores had 80% concordance; the novel score reclassified 20% of Khorana score (3530 low‐to‐high with 9.0% VTE; 734 high‐to‐low with 3.4% VTE) and led to a 25% increment in VTEs captured in the high‐risk group. In conclusion, the novel score demonstrated consistent discrimination and calibration across cohorts with heterogenous demographics. It could become a new standard to select high‐risk populations for clinical trials and VTE monitoring.