Formal and informal venous thromboembolism risk assessment and impact on prescribing of thromboprophylaxis: a retrospective cohort study

BACKGROUND: Hospital-acquired thrombosis (HAT) is a leading cause of preventable death and disability worldwide. HAT includes any venous thromboembolic (VTE) event occurring in-hospital or within 90-days of hospitalisation. Despite availability of evidence-based guidelines for HAT risk assessment and prophylaxis, guidelines are still underutilised. AIM: To determine the proportion of patients who developed HAT that could have been potentially prevented with appropriate VTE risk assessment and prophylaxis at a large public hospital in New Zealand. Additionally, the predictors of VTE risk assessment and thromboprophylaxis were examined. METHOD: VTE patients admitted under general medicine, reablement, general surgery, or orthopaedic surgery service were identified using ICD-10-AM codes. Data were collected on patient characteristics, VTE risk factors, and the thromboprophylaxis regimen prescribed. The hospital VTE guidelines were used to determine rates of VTE risk assessment and the appropriateness of thromboprophylaxis. RESULTS: Of 1302 VTE patients, 213 HATs were identified. Of these, 116 (54%) received VTE risk assessment, and 98 (46%) received thromboprophylaxis. Patients who received VTE risk assessment were 15 times more likely to receive thromboprophylaxis (odds ratio [OR] = 15.4; 95% CI 7.65–30.98) and 2.8 times more likely to receive appropriate thromboprophylaxis (OR = 2.79; 95% CI 1.59–4.89). CONCLUSION: A large proportion of high-risk patients who were admitted to medical, general surgery and reablement services and who developed HAT did not receive VTE risk assessment and thromboprophylaxis during their index admission, demonstrating a significant gap between guideline recommendations and clinical practice. Implementing mandatory VTE risk assessment and adherence to guidelines to improve thromboprophylaxis prescription in hospitalised patients may help reduce the burden of HAT. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s11096-023-01578-w.