Number of new heart failure cases in the UK is on the rise
"Heart failure kills more Britons than the four most common cancers," is the inaccurate headline from the Mail Online.
Heart failure is when the heart is unable to pump blood around the body properly. It's often a complication of an underlying health problem, such as high blood pressure or coronary heart disease.
Researchers compared the number of heart failure cases in the UK from 2002 to 2014. They found that new cases of heart failure increased by 12% from 2002 to 2014.
The total number of new cases recorded in 2014 is similar to the number of new diagnoses of 4 of the most common causes of cancer (lung, breast, bowel and prostate) combined. But crucially, the researchers didn't look at the death rate from any of these conditions.
The Mail Online's suggestion that this research "points to increasing levels of obesity as a part of the reason for the rise" isn't strictly accurate.
It's a reasonable assumption to make, but researchers didn't specifically investigate the effect of other conditions on the heart disease rate.
Instead, they looked at how differences in socioeconomic status affected the number of heart failure cases in the UK. And they found a strong link between low socioeconomic status and heart disease rates.
Where did the story come from?
The study was carried out by researchers from the University of Oxford, the University of Bristol, the University of Southampton, University College London, the University of Glasgow and Imperial College London.
It was funded by the British Heart Foundation and the National Institute for Health Research.
The study was published in the peer reviewed journal The Lancet on an open access basis and is free to read online.
The Mail Online accurately reported there were 190,798 new cases of heart failure in the UK in 2014, but failed to explain that this figure is partly the result of an increase in population size and an ageing population.
When these factors were taken into account in the statistical analysis, the proportion of the population with heart failure (incidence) actually decreased by 7% for both men and women.
And the study didn't look at deaths arising from heart failure. It only looked at the number of confirmed new cases of heart failure as recorded in health records.
What kind of research was this?
This 12-year population-based cohort study looked at patients' electronic health records from primary and secondary care.
These records are made up of information on people's health gathered routinely by healthcare staff, and are stored in an electronic database called the Clinical Practice Research Data Link (CPRD).
Cohort studies are good for estimating incidence (a measure of the burden of disease in a population per year) and comparing disease burden over time.
They're also useful for looking at links between factors – in this study, how a person's age and other conditions they have may influence whether they develop heart failure or not.
Cohort studies aren't able to prove that one factor causes another. A randomised controlled trial would be most appropriate for this.
But giving one group of people a treatment to prevent heart disease and not treating the other group could be seen as unethical if there was an expected benefit for the people receiving treatment.
What did the research involve?
The researchers used CPRD data of more than 4 million people in the UK between 2002 and 2014 to see who developed heart failure.
People were eligible if they were 16 years or older and had been registered with their general practice for at least 12 months.
Researchers excluded people from the study if they had a diagnosis of heart disease before the study started or within the first 12 months of them being registered at their general practice.
The researchers first calculated the crude rates, or the total number of people with heart failure each year divided by the total population.
Areas with older populations were expected to have higher crude rates, because heart disease incidence generally increases with age.
With this in mind, the researchers then calculated the standardised rate of heart failure, which takes into account differences between populations that may affect people's chances of developing the disease.
To take into account and adjust for these differences, the researchers made sure they collected:
- number of comorbidities (other illnesses)
- socioeconomic status
- region in which they lived
The total number of people newly diagnosed with heart failure in 2002 was compared with the number diagnosed with heart failure in 2014.
What were the basic results?
Out of the sample, 93,074 people were diagnosed with heart failure: 45,647 women and 47,427 men.
The researchers reported the following results:
- From 2002 to 2014, heart failure incidence (adjusted for age and gender) decreased by 7% for men and women, from 358 to 332 per 100,000 person-years, an estimate of how many people will develop a specific condition over the course of a year (adjusted incidence ratio 0.93, 95% confidence interval [CI] 0.91 to 0.94).
- The estimated total number of people living with heart failure in the UK increased by 23%, from 750,127 in 2002 to 920,616 in 2014.
- The average age at first presentation of heart failure increased from 76.5 years old to 77 years old.
- The average number of other conditions at first presentation of heart failure increased from 3.4 to 5.4.
- Socioeconomically deprived people were 61% more likely to develop heart failure than those from the most affluent group (incidence rate ratio 1.61, 95% CI 1.58 to 1.64) and developed the condition on average 3.5 years younger (adjusted difference -3.51, 95% CI 3.77 to 3.25).
- Socioeconomically deprived individuals also had a higher number of other conditions, such as diabetes and chronic obstructive pulmonary disease (COPD), despite their younger age.
How did the researchers interpret the results?
The researchers stated: "Despite a moderate decline in standardised incidence of heart failure, the burden of heart failure in the UK is increasing, and is now similar to the 4 most common causes of cancer combined."
As the researchers also looked at other factors that influence heart failure rate, they commented: "The observed socioeconomic disparities in the disease incidence and age at onset within the same nation point to a potentially preventable nature of heart failure that still needs to be tackled."
This study had some definite strengths.
- The researchers took into account population characteristics, such as age, socioeconomic status and information on other health conditions, which allowed them to examine how these factors might affect the development of heart failure.
- There was a balanced representation of age groups, genders and the numbers of people in each socioeconomic group.
- This all means we may be able to apply these findings not only across the UK, but also possibly to other developed countries, as heart failure and population ageing trends in this study are similar to those of other countries.
As ever, there are some limitations. While electronic health records record some things well, underreporting of disease diagnosis is common and can vary between GP practices and hospitals.
The researchers reported it was very difficult to find all types of heart failure in the health records, meaning some types – perhaps the more common – were frequently reported, while the rarer types less so.
The reliability of electronic health records has been studied a lot, and despite some underreporting being present, you can expect an average of 89% to 92% completeness.
This study has implications for deciding appropriate levels of healthcare to support the growing number of people who have heart failure – and prevent new cases.
Although the decline in standardised heart failure incidence suggests heart failure prevention has improved, the researchers think this could be down to changes to the environment, public health measures, and improvements in clinical care and treatments.
Despite this, overall numbers of new cases of heart failure in the UK are rising, meaning there's more pressure on the health service.
This study shows there are differences in heart failure rates depending on people's age and how deprived they are. This means it's possible for future public health efforts to target certain at-risk groups.
You can lower your risk of heart failure by making healthy changes to your lifestyle, such as taking regular exercise, stopping smoking, and eating a healthy diet to stay a healthy weight.
If you're experiencing symptoms of heart failure, such as persistent breathlessness and feeling very tired after physical activity, you should see your GP.
Analysis by Bazian
Edited by NHS Choices
Links to the headlines
Heart failure kills more Britons than four most common cancers: Unhealthy lifestyles leads to a surge in cases over the past decade
Mail Online, November 21 2017
Links to the science
Conrad N, Judge A, Tran J, et al. Temporal trends and patterns in heart failure incidence: a population-based study of 4 million individualsThe Lancet. Published online November 21 2017