Our material from Vestfold country included 182 patients with a first-time spontaneous intracerebral haemorrhage. This is the largest prospective study of brain haemorrhages undertaken in Norway. We found a total incidence for first-time intracerebral haemorrhages of 20.5/100 000/year. This is likely to be a minimum incidence, since some patients from Vestfold county may have sustained a brain haemorrhage while outside the county without being transferred to Vestfold Hospital. Some patients with small haemorrhages may also have not been admitted to hospital.
Few Norwegian studies have been made of the incidence of intracranial haemorrhages. A study from the Innherred district from the years 1994 – 96 reported a total incidence of intracerebral haemorrhage of 32/100 000/year (3). This study also included patients with recurring haemorrhages. A large Norwegian study of intracerebral haemorrhages undertaken in the country’s southernmost region in 134 patients found a total incidence of 17.6/100 000/year for first-time haemorrhages (4). Haemorrhages from vascular malformations were not excluded in this study, but three patients with an isolated intraventricular haemorrhage were excluded. Age-adjusted to the standard European population from 1976 we found a total incidence of 13.7/100 000/year, which is consistent with the study from Norway’s southernmost region (12.5/100 000/year). In general, the European population has aged since 1976, and we found an age-adjusted incidence for the standard European population in 2010 of 22.8/100 000/year (9).
An international meta-analysis found an incidence of spontaneous intracerebral haemorrhages of 24.6/100 000/year (2). There were major differences between countries. Many of the studies included also encompassed patients with undefined cerebral stroke, as well as patients who had not undergone any radiological examination. A large, prospective study from southern Sweden found an incidence of primary intracerebral haemorrhage of 30.0/100 000/year (11).
Spontaneous intracerebral haemorrhage affects primarily the oldest part of the population, and the incidence increases with age. In the age group older than 90 years we found a somewhat lower incidence than in the age group 80 – 89 years. There are few patients in this group and the confidence intervals are overlapping, so this finding might not be genuine. However, the study from southern Sweden also showed a non-significant, reduced incidence of intracerebral haemorrhages in men in the oldest age group (≥ 85 years) (11).
The prognosis is poorest for the oldest patients. Those who died from their haemorrhage were significantly older than those who survived. A large haemorrhage volume upon admission was associated with a poor prognosis. It is known that a haematoma may expand somewhat during the first 24 hours after the onset of bleeding (12). We have only measured the volume of the haematoma at the admission stage.
Spontaneous or primary intracerebral haemorrhage is not an unambiguous designation. Most incidence studies have excluded patients with traumatic brain haemorrhage, haemorrhage in a tumour, bleeding after thrombolytic treatment, subdural haematoma and haemorrhage from aneurysms, as we also have done. Some studies have also excluded patients with arteriovenous malformations. We have included patients with acute haemorrhages from such malformations to facilitate comparisons with the other Norwegian incidence studies.
While the frequency of ischaemic stroke has declined during the last decades, it remains uncertain whether this also applies to cerebral haemorrhages (2, 13, 14). This may be caused by the increasing use of anticoagulant treatment during the same period (13). International data differ substantially, however. A Finnish study shows a reduction in warfarin-related haemorrhages and reduced mortality, despite the increasing use of warfarin over time (15).
Most often, the symptoms of a brain haemorrhage occur acutely and alarmingly. Most patients are therefore brought quickly to hospital. In our material, altogether 89.9 % of the patients were admitted within the first 24 hours after symptom onset. The average number of hospitalisation days for patients with a spontaneous intracerebral haemorrhage amounted to 9.4 days. This is a longer hospitalisation period than for other types of cerebral stroke. In 2014, the average number of hospitalisation days for patients with all types of brain strokes at Vestfold Hospital amounted to 5.7 days (1).
The use of anticoagulants gives rise to an increased risk of intracerebral haemorrhage. In our study, the use of warfarin was associated with a significantly increased mortality. Other studies have found the same (4). The novel oral anticoagulants were introduced towards the end of the inclusion period, and we have therefore no relevant data for these drugs. Studies have shown that they are likely to involve a lower risk of intracerebral haemorrhage than warfarin (16).
The use of platelet inhibitors also entails a higher risk of intracerebral haemorrhage (17). We found that those who used platelet inhibitors had a non-significant, increased mortality when compared to patients who did not undergo any anticoagulant treatment.
Hypertension is a key risk factor for both ischaemic stroke and cerebral haemorrhage. More than half of our patients suffered from hypertension.
Over a number of decades, the prognosis for stroke patients has improved (18). This mainly applies to ischaemic stroke. Spontaneous cerebral haemorrhage remains a serious condition with high mortality. In our material, the 30-day mortality amounted to 39.6 %. This concurs with the other Norwegian studies from the Innherred district (37.8 %) (3) and the country’s southernmost region (36.6 %) (4).In an international meta-analysis, median mortality after 30 days amounted to 40.4 % (2). In another review article, 30-day mortality amounted to 42 % (19). In a large retrospective Finnish study, altogether 51 % of the patients had died after 28 days (20). It might seem as though the mortality from spontaneous brain haemorrhage has remained fairly constant over several decades (2).
A previous material from a large international study showed that patients with a haemorrhage in the right brain hemisphere had a higher risk of death within 90 days than those with a haemorrhage in the left hemisphere (21). No such difference was found in our material.
Most patients with a spontaneous intracerebral haemorrhage are treated conservatively (22). A markedly elevated blood pressure may cause increased growth of haematomas and ought to be lowered. According to guidelines from the European Stroke Association (ESO) from 2014, it is safe to lower the systolic blood pressure to < 140 mm Hg within six hours after symptom onset, and this is possibly better than a systolic target of < 180 mm Hg (23). However, this is a tentative recommendation.
In warfarin-associated haemorrhages, the anticoagulant treatment should be reversed and the INR values normalised wherever possible. For haemorrhages associated with the use of dabigatran an antidote is now available – idaruzisumab.
Surgical treatment is recommended for haemorrhages in the cerebellum and from arteriovenous malformations (24). External drainage is also relevant in cases of threatening hydrocephalus. The benefits of evacuating supratentorial haematomas are uncertain (25). A large randomised study showed no definitive effect of early surgery of supratentorial haematomas when compared to conservative treatment (25). Nor did a meta-analysis show any better effect of surgery when compared to conservative treatment of such haematomas (26).
Approximately half of those who survived their brain haemorrhage had few sequelae and returned to their homes without any need of extra help or supervision. These had a Barthel ADL index score of 19 or 20, meaning that they were self-reliant in their daily activities. Most of those who were living at home had an mRS value ≤ 2, which is deemed a good outcome after a brain stroke.