Brendan Shaw
More people on the planet die from cardiovascular disease than any other illness or injury.
Cardiovascular disease is defined as disorders of the heart and blood vessels. It includes coronary heart disease, cerebrovascular disease, rheumatic heart disease and other conditions. Four out of five deaths from cardiovascular disease occur due to heart attacks and stroke and one-third of deaths occur prematurely to people under the age of 70.
Global trends
Cardiovascular disease kills 18 million people in the world every year, through a combination of heart attacks, stroke and heart failure. This 18 million people represent 31% of all deaths around the world.
Source: WHO Health Observatory, https://www.who.int/en/news-room/fact-sheets/detail/the-top-10-causes-of-death, accessed 21/6/2020.
With the global rise in non-communicable diseases (NCDs), cardiovascular disease has become the most common way people die. In a strange way, this is the result of a good news story: more people are dying from NCDs like cardiovascular disease because less are dying from communicable diseases. Higher life expectancy worldwide is contributing to an ageing population. This means that more people are dying from diseases like cardiovascular diseases associated with ageing.
The number of people worldwide with cardiovascular disease is growing. The immediate risk factors for cardiovascular diseases include poor diet, smoking, lack of physical activity, high blood pressure and high cholesterol.
But in more good news, the worldwide death rate from cardiovascular disease has been steadily falling for decades. Thirty years ago, for every 100,000 people on the planet, 335 of them died from cardiovascular disease. By 2017, this had fallen to 233 per 100,000 people - a fall of more than 30% in almost three decades. This is a great achievement that has resulted from a combination of things like reductions in smoking, better diet and exercise, better health care, scientific discovery and access to medical technology.
Country level analysis
But the really interesting pictures emerge when you look at trends in the data at the country level.
What is fascinating is how different countries perform compared to each other, both in terms of their relative death rates from cardiovascular disease and their relative success in reducing these over the last quarter of a century. What becomes clear is that the reduction in cardiovascular death rates is not uniform across the world. Some countries have low base death rates, some have high death rates, some have done a good job of reducing theirs over time, while other countries have actually seen their cardiovascular death rates increase over the period.
This chart below takes raw data on cardiovascular deaths per 100,000 from 1990 to 2017 from the 'Our World in Data' site collated by the Global Change Data Lab and Oxford Martin School at Oxford University combined with my analysis. For each country, it plots deaths from cardiovascular disease per 100,000 people in 2017 against that country's average annual growth rate (or rate of reduction) over that period. The data covers 194 countries.
There are many stories in this chart, but a look at the data tells us several things, including:
The average number of cardiovascular deaths per year in each country is 264 people per 100,000 - more than the total global amount of 233 because it is an average of all countries.
Countries around the world have reduced their cardiovascular death rates by 1.5% each year on average since 1990. A great achievement.
There are wide disparities in the success of countries in preventing cardiovascular deaths. South Korea is, by far, the best performing country in the world. By 2017 it was recording only 86 cardiovascular deaths per 100,000 people. This compares with the average of 264 for countries worldwide. South Korea has also done the best job of reducing its death rate, seeing an average reduction in the death rate each year of 5.24%, more than three-and-a-half times the average of all countries. This is extraordinary and helps explain South Korea's ageing population and why the country has one of the longest life expectancy rates in the world. The reasons for this fall would be many and varied but would include things like diet, exercise trends and access to healthcare.
Uzbekistan is the heart attack and stroke capital of the world with the worst performance worldwide. Uzbekistan has the dubious distinction of having a cardiovascular death rate of 724 people per 100,000 - 2.7 times higher than the global average. Not only that, but Uzbekistan also leads a dubious club of countries which saw their cardiovascular death rate increase each year. Uzbekistan saw its death rate increase by an average of 1.8% each year since 1990. To give you a sense of the scale of the difference, an Uzbek is around 8.5 times more likely to die of a heart attack or stroke than a South Korean.
High income countries perform better overall. In general, richer countries have lower rates of cardiovascular deaths and have done a better job over the last few decades of securing reductions in these. As with many NCDs, money - or the lack of it - plays a part in determining how well diseases are managed. Generally speaking, the bottom left hand quadrant of the chart - where countries have both a low cardiovascular death rate and have done a good job of reducing this rate over the last three decades - is dominated by high income countries.
There are intriguing trends in the types of countries that dominate the upper right quadrant - those countries that have very high death rates and have seen their rates increase on average each year since 1990. Sadly, several groups of countries stand out as performing particularly poorly here. (1) The 'Stans': Uzbekistan, Azerbaijan, Afghanistan, Turkmenistan, Kazakhstan, Tajikistan, Pakistan and Kyrgyzstan all have high death rates and several have seen their rates increase; (2) Pacific Island Nations: Papua New Guinea, the Marshall Islands, Vanuatu, Fiji, Kiribati, Micronesia and the Solomon Islands also all congregate in this quadrant; (3) Eastern European countries: Ukraine, Belarus, Russia, Serbia and Bulgaria are all in this quadrant as well. Setting aside the Pacific Island nations, there almost seems to be an arc of high cardiovascular deaths stretching from the Central Asian Republics through to Eastern Europe.
There is also a group of countries with the unfortunate distinction of seeing an increase in death rates on average each year over the last three decades while the rest of the world saw them fall. Standout countries in this category include Uzbekistan, Azerbaijan, Lesotho, Zimbabwe, the Philippines, North Korea, Bangladesh and Pakistan.
Wealth, income and investment in health systems are important for reducing death rates. We know that genes and race don't explain much of the difference and we can demonstrate this by comparing North and South Korea. Both countries have Koreans living there and both share similar histories and cultures - families are even often split between the two countries. But their cardiovascular death rates are wildly different. North Korea's death rate is so much higher today that Koreans living there are 3.5 times more likely to die from cardiovascular disease than their southern cousins, simply because they live north of the Korean Demilitarised Zone. North Korea is a low income country with poor health systems and the results show in how many of its citizens die from heart disease and stroke compared to people in South Korea.
Of course, there are many more stories in the data, but the underlying story coming out is that while the world, collectively, is doing well in reducing cardiovascular death rates, not all countries are seeing the same benefits.
Going forward
While the immediate causes of cardiovascular disease are well known, such as poor diet, lack of exercise, lack of available care, smoking, excessive alcohol use and lifestyle, the secondary causes are things like income level, poverty, cultural change and ageing, or what the World Health Organization has called the 'causes of causes'.
As an aside, the issues that sometimes get raised in access to medicines, such as patents and affordability of medicines, are less relevant here. There are many classes of cardiovascular medicines, including beta blockers, ace inhibitors and AIIRAs for high blood pressure, statins for high cholesterol and direct thrombin inhibtors for thinning the blood and reducing blood clots where patents have expired. These are all now genericised medicine classes with cheap, often old, generic medicines, such that issues that are sometimes raised such as patents and affordability of medicines should not be a problem, at least when it comes to old technology.
Whatever the reason, clearly there is further work to be done in treating cardiovascular disease and preventing deaths. Many of the countries with high death rates also have high preventable death rates, meaning that the prevention strategies being implemented in other countries are not being implemented in these poorer performing countries.
This makes it all the more important that we continue to press ahead with global strategies to treat cardiovascular disease and ensure that everyone can benefit from the improvements in health care and technology regardless of where they live.