Alarming Differences In Incidence And Mortality Of Devastating Brain Haemorrhage Across NZ

A groundbreaking AUT study has revealed life-threatening brain haemorrhages, a type of stroke, are more common and deadlier in rural Aotearoa than in urban areas.

The findings, published in Lancet Regional Health - Western Pacific, are “alarming” according to Dr Ilari Rautalin, Associate Professor of Neurosurgery at National Institute for Stroke and Applied Neurosciences (NISAN).

The study found that brain haemorrhages were almost twice as common and 1.5 times more deadly in many rural regions compared to areas close to hospitals with neurosurgical units. There are currently five in Aotearoa – Auckland City, Waikato, Wellington, Christchurch and Dunedin Hospitals.

“These results show a need for urgent investigations to explore whether the prevention, diagnostics and treatment of subarachnoid haemorrhage (SAH) varies within New Zealand,” says Dr Rautalin.

Despite a relatively low mean age among the working-age population in Aotearoa, SAH is the most devastating type of stroke, killing almost half of those affected.

The new study identified all 5,500 people developing new SAH across New Zealand over 18 years during the early 21st century. Based on the study, women, Māori and Pacific peoples as well as residents in some of the North Island’s rural districts such as Tairāwhiti, Northland and Whanganui had the highest incidence of SAH.

Moreover, residents of many South Island districts such as Southern, West Coast and Nelson Marlborough had an exceptionally high risk of dying after SAH.

Efficient prevention and timely hospitalisation are likely key factors for future improvements.

“Although our study cannot determine direct causes for observed differences, we know that the prevalence of smoking, one of the most important risk factors for SAH, is the highest in population groups and districts with the highest incidence of SAH,” says Dr Rautalin.

“Since the current evidence suggests that the majority of SAH cases and other life-threatening stroke types could be prevented by eliminating smoking and high blood pressure from the populations, actions towards the reduction of these two risk factors deserve to be prioritised.”

Regarding poor prognosis, the study shows most deaths due to SAH happen before patients are admitted for life-saving neurosurgical treatment.

Making people better aware of SAH’s symptoms could lead to more timely diagnostics, with hospitalisation then acting as a crucial factor to decrease high mortality, says Dr Rautalin.

“Contrary to brain infarction and other brain haemorrhages that frequently cause face drooping, arm weakness, and speech difficulty, the most common symptom of SAH is a severe headache with sudden onset.

“This so-called thunderclap headache is often described as the worst headache of a person’s life that starts as fast as a lightning strike.”

Director of NISAN, Professor Valery Feigin agrees there’s an urgent need for more efficient prevention and treatments to decrease the burden of SAH and other neurological disorders.

“We know that neurological disorders are the leading cause of health burden in the world which underlines the importance of their prioritisation in healthcare planning and resource allocation,” Professor Feigin says.

“Even though their age- and population-standardised burden is generally decreasing, the absolute burden of neurological disorders is constantly increasing. This suggests that our current prevention, treatment and rehabilitation strategies are not sufficient to halt the increasing number of cases, deaths and disabilities due to the growing population and life expectancy.”

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