Temporal validation of the electronic health record cancer-associated thrombosis model in patients with low bleeding risk.

BACKGROUND

The electronic health record cancer-associated thrombosis (EHR-CAT) model was derived to predict cancer-associated venous thromboembolism (VTE). Prior validations often relied on cancer registry data with reporting delays.

OBJECTIVES

We aimed to perform an external temporal validation of the EHR-CAT model among patients at low risk of bleeding using contemporary Veterans Affairs electronic health record data.

METHODS

We conducted a retrospective cohort study in patients with active cancer who received systemic therapy within the national Veterans Affairs (VA) health care system from 2017 to 2024. The key inclusion criteria included: (1) having readily extractable data for EHR-CAT calculation without cancer registry data, (2) index date at first or subsequent lines of therapy, (3) exclusion of adjuvant endocrine monotherapy with low risk for VTE, and (4) application of anticoagulant clinical trial exclusion criteria to minimize bleeding risk. Patients from previously published studies were excluded. Systemic therapies were defined using the VA Corporate Data Warehouse, and one line was randomly selected. VTE outcomes were determined using validated VTE-Bidirectional Encoder Representations from Transformers natural language processing from clinical notes. Time-dependent C-statistic and calibration slope were assessed.

RESULTS

Among 65,341 patients with cancer receiving systemic therapy (42,865 first-line and 22,476 second-line or higher), median age was 71.9 years, and 95% were male. Most common cancers included prostate (16.1%), lung (14.8%), lymphoma (11.5%), and bladder (11.1%). The VTE incidence at 6 months was 5.4%. VTE was observed in 1.9%, 4.0%, 4.7%, 6.5%, 9.6%, and 12.3% of patients with EHR-CAT scores 0-, 1, 2, 3, 4, and 5+, respectively (C-statistic 0.67). Calibration slope was 0.876.

CONCLUSION

The EHR-CAT model, when applied across different lines of therapy, demonstrated similar performance as in previous studies.