Incidence of intracerebral and subarachnoid haemorrhage in southern Sweden

Objectives-Spontaneuos intracranial haemorrhage-that is, mainly subarachnoi d haemorrhage (SAH) and primary intracerebral haemorrhage (PICH)-constitute s an important part of all strokes. As previous epidemiological studies hav e demonstrated highly variable incidence rates, we conducted a large prospe ctive investigation of all haemorrhagic strokes during a 1 year period. Methods-Twelve hospitals serving a defined population of 1.14 million in so uthern Sweden registered all cases with spontaneous intracranial haemorrhag e, including those found dead outside hospitals, during 1996. All patients were examined with CT of the brain or underwent necropsy. Incidence rates a djusted to the Swedish population for age and sex, as well as location of h aematoma and prevalence of risk factors were calculated. Results-A total of 106 patients with SAH and 341 patients with PICH were id entified. The annual incidence/100 000 was 10.0 (6.4 for men and 13.5 for w omen) for SAH and 28.4 (32.2 for men and 24.7 for women) for PICH when adju sted to the Swedish population. Subarachnoid haemorrhage affected twice as many women as men. The incidence of both types of haemorrhage increased wit h advancing age, but in particular, this was the case for supratentorial PI CH. Lobar haematomas were the most common (51.6%) type of PICH. Among patie nts with PICH, 37% had hypertension, 41% other vascular disease, and 12% we re on oral anticoagulation. Among patients with SAH, 28% had hypertension a nd 18% vascular disease before the haemorrhage but no one was on treatment with oral anticoagulation. Conclusions-The incidence of PICH was high, especially for the older age gr oups. PICH was, on average, three times as common as SAH. The study undersc ores the importance of PICH and SAH as significant stroke subgroups.