Hypertension is a risk factor for subarachnoid hemorrhage and is also considered a risk factor for saccular intracranial aneurysm (sIA) formation. However, there is little direct evidence that antihypertensive medication will reduce sIA formation.

The impact of antihypertensive medication on de novo sIA formation was studied in an angiographically followed cohort of 1419 patients. Patients were identified from our population‐based Kuopio Intracranial Aneurysm Database, and data on the purchases of antihypertensive medication were obtained from a national registry. Univariate and multivariate analyses were used to investigate the risk factors.

Of the 966 sIA patients who were prescribed with antihypertensive medication, 841 patients used the medication regularly; 20 of them had de novo sIA. One hundred and twenty‐five patients used the medication irregularly and 12 of them developed de novo sIAs. Four hundred and fifty‐three patients did not use antihypertensive medication even though 27 of them had a diagnosis of hypertension, and 10 of them developed de novo sIAs. In the multivariate analysis antihypertensive medication did not significantly reduce de novo sIA formation (hazard ratio [HR] 1.60, 95% confidence interval [CI] 0.84–3.06). Age at primary diagnosis (HR: 0.95, 95%: CI 0.93–0.98) and smoking history (HR: 5.53, 95% CI: 2.77–11.05) were significant risk factors for de novo sIA formation. Also, irregular usage of antihypertensive medication was a significant risk factor (HR: 3.84, 95% CI: 1.59–9.29) for de novo sIA formation.

Antihypertensive agents were not associated with a reduction of de novo sIA formation, but irregular use of antihypertensive agents was associated with an increased risk of de novo sIA formation.