Can We Use Routinely Collected Healthcare Data for a Nationwide Trial on Venous Thromboembolism Prophylaxis Following Primary Joint Replacement? A Feasibility Study.

BACKGROUND: UK hospitals nationally report venous thromboembolism (VTE) within 90 days of hospital admission, with hospital-acquired thrombosis (HAT) registers at each center used for this. We assessed the accuracy of our HAT register in identifying VTE following primary total hip arthroplasty (THA) and total knee arthroplasty (TKA).
METHODS: We assessed 982 elective admissions for primary THA and TKA at a large tertiary center during 2018. The primary outcome was any VTE (deep vein thrombosis and/or pulmonary embolism) within 90 days postsurgery. VTEs were identified by systematically searching hospital databases (including discharge and outpatient letters, readmissions, emergency department visits, and imaging) for every patient. VTEs were also collected using the HAT database at our center, which is maintained regularly by a specialist nursing team and used to report VTEs nationally. Diagnostic test characteristics were assessed for HAT in identifying VTEs compared to the gold standard (ie, VTEs from the hospital databases).
RESULTS: The prevalence of VTE was 2.7% (n = 27), with 20 VTEs identified by HAT. The accuracy of HAT in identifying VTEs were as follows: sensitivity = 74.1% (95% confidence interval [CI] = 53.7-88.9), specificity = 100% (CI = 99.6-100), positive predictive value = 100% (CI = 83.2-100), and negative predictive value = 99.3% (CI = 98.5-99.7).
CONCLUSION: One-quarter of VTEs occurring after THA and TKA were not identified by the HAT register. These cases would be missing when our hospital's data are sent for national VTE reporting, and therefore would have substantial implications if HAT was primarily used to identify VTEs in a trial. Further work is needed to improve the accuracy of HAT VTE reporting before this could be relied upon in this setting.