Regional differences in the incidence of aneurysmal subarachnoid haemorrhage in Finland.

BACKGROUND: Over the years, the consensus has generally been that Finland is a country with a significantly high incidence of aneurysmal subarachnoid haemorrhage (SAH) when compared to the rest of the world, excluding Japan. Most of the traditionally cited Finnish incidence studies are several decades old and have clear differences in their methodology and study design. The objective of this study was to determine the hospital-admitted incidence of aneurysmal SAH at Tampere University Hospital between 1990 and 2014. We also compared the incidence to other geographical regions in Finland. METHODS: The material for this study consists of patients admitted to Tampere University Hospital between 1990 and 2014 with the presentation of aneurysmal SAH. There was a total of 1965 patients with aneurysmal SAH in our data. RESULTS: The mean hospital-admitted aneurysmal SAH incidence over the period was 7.41 per 100,000 person-years. The hospital-admitted aneurysmal SAH incidence in the Eastern Finland region was two-thirds greater than in the Tampere University Hospital region. CONCLUSIONS: We observed a relatively steady hospital-admitted incidence of aneurysmal SAH (7.41 per 100,000 person-years) in the Tampere University Hospital region. This result is parallel to a recent study looking into the incidence of aneurysmal SAH for the whole of Finland. Compared to the Tampere University Hospital region, the incidence was 64% greater in the Eastern Finland region.