National Trends in Venous Thromboembolism incidence in Ireland (2015-2022): A Retrospective Analysis

Background Venous thromboembolism (VTE) affects millions globally resulting in significant costs to patients and healthcare systems. Robust incidence data on VTE are limited, with a scarcity of national-level data in Ireland. Methods This was a retrospective observational study using Hospital Inpatient Enquiry (HIPE) data obtained from hospital admissions in Ireland from 2015–2022. VTE events were identified using International Classification of Disease codes and categorised into primary (reason for admission) and secondary (arising during admission), and hospital-acquired VTE (HA-VTE). Census data were used to calculate crude incidence rates. Secondary rates were calculated per 1,000 inpatient discharges and per 1,000 elective hip/knee arthroplasty's. Results Between 2015–2022, 51,123 adult VTE cases were recorded, with a mean annual crude incidence of 172 per 100,000 population. The mean adult primary VTE crude incidence was 98 per 100,000, and mean annual HA-VTE rate was 9.9 per 1,000 discharges. 15,284 (52%) of primary VTE were in females. A total of 218 paediatric VTE cases were identified (0.23 per 10,000 population). Pregnancy-associated VTE (PA-VTE) accounted for 2.4 VTE events per 1,000 live births. The mean incidence of VTE was 11 per 1,000 elective hip/knee arthroplasty's. Conclusions This national report of VTE incidence in Ireland provides data on primary and secondary VTE trends. From 2020–2022, increases in paediatric VTE, adult pulmonary embolism and pregnancy-associated VTE and decreases in adult deep vein thrombosis were observed, in part due to the COVID-19 pandemic. This forms essential baseline data to inform VTE prevention, surveillance, further research, and health policy.