The unchanging pattern of subarachnoid hemorrhage in a community

TLDR

In Rochester, Minnesota, the annual incidence of aneurysmal subarachnoid hemorrhage has remained stable at about 11 per 100,000, with age‑specific rates increasing with age and survival depending on clinical grade, time to onset, and intracerebral hematoma. Among patients who survived to receive care, 48 % were grade 1–2, 20 % grade 3, and 32 % grade 4–5, and 20 % experienced rebleeding within 10 days of the initial hemorrhage.

Abstract

The average annual incidence of subarachnoid hemorrhage (SAH) from aneurysm rupture in Rochester, Minnesota, has remained remarkably constant at about 11 per 100,000 population. Age-specific incidence increased with age. Survival after SAH depended on: (1) clinical grade, (2) time after onset of SAH, and (3) presence of intracerebral hematoma. Among those who survived to receive medical attention, 48% were clinical grade 1 or 2, 20% were grade 3, and 32% were grade 4 or 5. Proved rebleeding occurred within 10 days of the first SAH in 20% of patients who survived until hospital admission.