New research published in the European Heart Journal has shown stroke-related death rates are declining overall in Europe, but in some countries the decline is levelling off or death rates are even increasing.
Cerebrovascular disease includes strokes, mini-strokes, and narrowing, blockage or rupturing of the blood vessels supplying blood to the brain. It is the second single largest cause of death in Europe after heart disease, accounting for 9% of deaths in men and 12% of deaths in women each year. Stroke-related death rates have been a major factor in public health.
How have stroke-related death rates changed?
The EHJ study used data from the World Health Organization (WHO) to examine mortality trends in three particular types of cerebrovascular disease in Europe for 37 years between 1980 and 2016: ischaemic stroke, haemorrhagic stroke and sub-arachnoid haemorrhage (SAH), in which bleeding occurs between the brain and the surrounding membrane.
The researchers, led by Dr Nick Townsend, associate professor in public health epidemiology at the University of Bath, UK, found that across the whole of the WHO European region for the most recent period for which data were available, there had been significant decreases in death rates from all three types of cerebrovascular disease 65% of countries for men and women.
However, there had been increases in three countries (6%) for men (Azerbaijan, Georgia and Tajikistan) and in two countries (4%) for women (Azerbaijan and Uzbekistan).
Is it really in decline?
There was evidence of a recent plateau in trends where the rate of reductions in mortality in the most recent period was less pronounced than in the previous period. There were also a number of countries in which death rates showed no change over the most recent period. This means that in both sexes, more than one third of countries showed either a slowing of the decrease in death rates, no decrease, or an increase in the most recent trend.
Age-standardised 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.
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-standardised death rates.
“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 plateauing or 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.
What does this mean for the future of stroke-related deaths?
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. Possible reasons why the trends towards lower death rates might be levelling off or even increasing in some countries could include the increasing prevalence of obesity, diabetes and higher cholesterol levels in recent years.
Limitations of the study include the fact that the researchers used data submitted to the WHO by individual countries, and which were either absent or incomplete from some countries and of variable quality; the analytical approach used to identify trends is a simplified method and may not give the full picture of plateauing in some countries over some periods; and the study describes the trends but cannot give reasons for them.