Stroke Death Rates Decreasing Overall

The European Heart Journal published new research on 15 August showing that deaths from conditions affecting blood supply to the brain are declining in most of Europe, however, in some countries the death rates are increasing.

Cerebrovascular diseases include strokes and narrowing, blockage or rupturing of the blood vessels supplying blood to the brain, occupying the spot of second largest cause of death in Europe after heart disease, accounting for 9% of deaths in men and 12% of deaths in women each year.

The study used data from the World Health Organization (WHO) to examine mortality trends in three particular types of cerebrovascular disease in Europe between 1980 and 2016: ischaemic stroke (a lack of blood flow to the brain), haemorrhagic stroke (bleeding in the brain) and sub-arachnoid haemorrhage (SAH), in which bleeding occurs between the brain and the surrounding membrane, not all countries had data available for the full 37 years however.

Researchers led by Dr Nick Townsend, Associate Professor in Public Health Epidemiology at the University of Bath, UK, found that across the WHO European region, for the most recent data available, there had been a 65% decrease in death rates from all three types of cerebrovascular disease in 33 countries for men and women. However, there had been a 6% increase in Azerbaijan, Georgia and Tajikistan for men and 4% increase in Azerbaijan and Uzbekistan for women.

Age-standardized mortality rates from stroke, which adjust to take account of differences in population size and age structure, were higher in men than in women for all countries. For stroke, they were much lower in Western Europe than the rest of the continent. In Central Asia, they ranged from 152 in Armenia to 345 in Azerbaijan per 100,000. In the UK, the death rate was 68 per 100,000 in men and 65 per 100,000 in women.

When the researchers looked at each of the three types of stroke individually, data were only available by stroke subtype for 43 countries; most of the countries with missing data were in Eastern Europe and Central Asia. Over the whole period since 1980, more than half of countries with available data had significant decreases in age-standardized death rates from ischaemic stroke, 56% of countries in men and 51% in women, and haemorrhagic stroke 58% and 67% of countries respectively. However, eight countries had a 19% increase in death rates from ischaemic stroke among men and nine countries had a 21% in women, compared to none for haemorrhagic stroke.

“When we looked at the type of stroke and for the most recent period for which data were available, the trends could be quite different,” said Dr Townsend. “This shows that considering all cerebrovascular disease over the whole period hides a lot of the story. In the most recent period, there were increases in ischaemic stroke in eight countries among men and nine for women, increases in haemorrhagic stroke in three countries in men and one for women, and increases in SAH in five countries for men and eight countries for women. Over the last 35 years there have been large overall declines in deaths from cerebrovascular disease in the majority of European countries. While these declines have continued in more than half of the countries, these have not been consistent across Europe and our analysis has revealed evidence of recent plateauing and even increases in stroke deaths in certain countries. We have seen this in both sexes and in countries across the whole of Europe, particularly in Eastern and Central Europe and Central Asia. We have also found differences in death rates by stroke type. Therefore, it is not enough to consider cerebrovascular disease as just one condition and we must consider each individual stroke type.”

“Our findings highlight a need to counter inequalities by understanding local contexts in disease occurrence and treatment. In particular, we need to encourage the implementation of evidence-based recommendations in the prevention and treatment of stroke in all countries. Many countries have been able to reduce the mortality burden from stroke in recent years. We must understand why this is not happening in all countries and identify barriers to the implementation of evidence-based recommended practice in countries that are slow to adopt them. In addition, we only studied between-country inequalities, but we must consider within-country inequalities as well if we are to have an impact on the disease.”

The researchers say that SAH amongst women was the only type of stroke for which more countries demonstrated increasing trends than decreases in recent years. A less pronounced decrease, no significant change, or a significant increase in death rates from SAH, was found in 25 countries for women.

“General risk factors for SAH include familial predisposition and disorders of the blood vessels, leading to aneurysms. Smoking, hypertension and heavy drinking have also been found to be significant risk factors, as with other stroke types and cardiovascular disease,” said Dr Townsend. “Interestingly, when we compare mortality from stroke sub-type by age, we find that death from SAH is more common at younger ages. In the UK, for example, around 60% of deaths from SAH in women occur before the aged of 75, commonly termed premature. This is much lower in cerebral haemorrhage, which is closer to 25%, and lower still in ischaemic haemorrhage, which is around 15%. Despite SAH being much less common than the other stroke subtypes, this greater mortality at younger age groups needs further investigation and intervention.” – said Dr Nick Townsend

Although this study did not look at the reason behind these changes, he said it was unlikely that there was a single reason for the overall decline in cerebrovascular disease. Improvements in treating the disease, including new drugs and improved surgical techniques, played a role, as did prevention strategies that encouraged people to improve their lifestyles by stopping smoking, drinking less alcohol, improving their diet and taking more physical exercise.

By Shawn Wayne

23 August 2018 19:09