Use of UK national health databases for detecting intra-cranial aneurysm rupture in the Risk of Aneurysm Rupture (ROAR) study

The objective of this study was to determine the sensitivity of national databases for identifying aneurysm rupture events in patients with unruptured intracranial aneurysms and determine their suitability for follow-up for patients in the Risk of Aneurysm Rupture (ROAR) Study. ROAR is a longitudinal cohort study that has recruited 20,000 patients with unruptured intracranial aneurysms with detailed baseline clinical and imaging data collected for each participant. These patients will be followed-up using UK national databases for hospital admissions (HES-APC) and national databases of deaths (CRD) to identify aneurysm rupture events for the purpose of rupture risk prediction. To assess the suitability of national databases for this, a cohort of patients with unruptured intracranial aneurysms was identified at a single neurosurgery centre from records between 2006-2020. Patients were linked to the national databases to identify instances containing intracranial haemorrhage diagnosis codes. All returned hospital admissions underwent case note and CT scan review to confirm the true diagnosis or cause of death. Of 1,544 patients, 74 were identified to have suffered a subsequent aneurysmal rupture. The national databases of hospital admissions and deaths identified 57 hospital admissions for aneurysm rupture. The national database of deaths identified an additional 16 out-of-hospital deaths due to aneurysm rupture of which 11 (68.8%) were confirmed on post-mortem. Local hospital records identified one additional inpatient admission for aneurysm rupture. Based on the observed proportions of admissions missing from the national databases and local hospital records, an estimated 1.03 admissions for rupture were predicted to be missed by both. The estimated sensitivity of a national database search strategy for identifying admissions for aneurysm rupture was 96.6%, and 98.3% if combined with local hospital records. National databases can detect rupture events in patients with unruptured intracranial aneurysms with high sensitivity and are ideally suited to long-term follow-up in large longitudinal cohort studies.