Improvements in diagnosis and treatment over the past 30 years have led to a 17% decrease in the likelihood of death from aneurysmal subarachnoid haemorrhage (the bursting of a blood vessel on the surface the brain) in the general population, according to an Article published Online First and in the July edition of The Lancet Neurology.
In high-income countries aneurysmal subarachnoid haemorrhage (SAH) affects 8 in 100,000 people every year. It causes 5% of incident stroke cases and is associated with a poor outcome—about 30% of patients die within 24 hours and of those who survive more than a quarter are left disabled.
Recent advances in diagnosis and treatments including CT and MRI techniques for detection of aneurysms, dedicated stroke units, and endovascular coiling of burst aneurysms have greatly improved the prognosis of patients who reach hospital in good condition and are suitable for these treatments. However, whether these better diagnostic and management strategies have reduced the risk of death and disability from SAH in the general population is not known.
To answer this question, Dennis Nieuwkamp and colleagues from the University Medical Centre Utrecht, Netherlands, did a meta-analysis of 33 studies involving 8739 patients from 19 countries in five continents between 1973 and 2002. They adjusted the results for confounding factors such as age and sex, and also examined regional differences.
Findings showed that despite an increase in the average age of patients with SAH from 52 to 62 years, over three decades the likelihood of dying from a SAH has declined from 51% to 35%—a decrease of 0.6% per year. Adjustment for sex had no effect on the reduced risk of death, and a smaller but not statistically significant decrease was shown after adjustment for age—to 0.4% per year.
Interestingly, case fatality rates (proportion of people who die) in Japan were significantly lower (11.8% lower) than in Europe, USA, Australia, and New Zealand. No other regional differences in case fatality were found. The authors suggest that these regional differences may be the result of variation in the speed of patients' admission to hospital for the early occlusion of the aneurysm.
The authors conclude: "In future, case-fatality after SAH might decrease even more, owing to new diagnostic and therapeutic methods…[however the focus should also be on case-morbidity]…because of the high costs from the loss of productive life-years and the long-term care of patients with SAH who become and remain disabled from a young age."
In an accompanying Reflection and Reaction comment, Rustam Al-Shahi Salman and Cathie Sudlow from the University of Edinburgh highlight that two major challenges remain—aneurysm treatment in the elderly because of the aging population and the delivery of effective interventions for SAH in low to middle income countries, which bear the greatest global burden of SAH.
Dr Dennis Nieuwkamp, University Medical Centre Utrecht, Utrecht, Netherlands. T) +31(0) 88 755 8539 E) d.nieuwkamp@umcutrecht.nl
Dr Rustam Al-Shahi Salman, University of Edinburgh, Edinburgh, UK. T) +44 (0)79 7728 9895 (mobile) E) rustam.al-shahi@ed.ac.uk
For full Article and Reflection and Reaction, see: http://press.thelancet.com/tlnsah.pdf
Journal
The Lancet Neurology