Tuesday May 10 2016
Drugs and lifestyle changes are recommended for heart attack patients
"Thousands of heart victims killed by poor care," claims the Daily Mail.
A review of clinical data from the last 10 years in England and Wales looked at patients with a history of what are known as non-ST segment elevation myocardial infarction (NSTEMI) heart attacks.
NSTEMIs describe a class of heart attack that are serious enough to warrant hospitalisation, but don't pose as big a threat as typical heart attacks.
Data from almost 390,000 people who had an NSTEMI was included in the review. It found around 87% of patients did not receive one or more internationally agreed recommended interventions.
It has been estimated that if all patients had received all of the interventions recommended to them, 32,765 (28.9%) deaths may have been prevented over the 10-year period.
But an important consideration is that some of the interventions consisted of lifestyle advice, such as quitting smoking or changing diet. This means we cannot assume that all the people given such advice after a heart attack would follow it.
These findings are also limited by the possibility that data was missing or had been recorded incorrectly. The design of the study is not able to prove cause and effect, and there are a number of other factors beyond the recommended interventions that may have had an effect on survival.
The data is certainly worth considering – one preventable death is one too many – but it doesn't prove that "thousands of heart victims [were] killed by poor care", as reported by the media.
Where did the story come from?
The study was carried out by researchers from a number of institutions, including the University of Leeds and University College London.
Funding was provided by the British Heart Foundation and the National Institute for Health Research.
It was published in the peer-reviewed European Heart Journal: Acute Cardiovascular Care.
This study has been reported widely in the UK. And, while these reports have been accurate, none mention the inherent limitations of the study.
The Daily Mail and The Daily Telegraph both quote Professor Peter Weissberg, Medical Director at the British Heart Foundation, who said: "This study shows that many people in the UK are receiving suboptimal care after a heart attack and that lives are being lost as a consequence.
"Applying clinical guidelines in heart disease costs little, and in the long term saves money and, most importantly, saves lives."
What kind of research was this?
This cohort study used data from the UK national heart attack register to see whether guidelines for the care of patients who have had a non-ST elevation myocardial infarction (NSTEMI) is being followed.
An NSTEMI is a type of heart attack where the person has the symptoms of a heart attack and associated blood test results (raised heart enzymes), but they don't have the typical signs of heart attack (ST elevation) on an ECG monitor.
Typically, in an NSTEMI the blood supply to the heart is only partially, rather than completely, blocked. As a result, a smaller section of the heart is damaged. However, NSTEMI is still regarded as a serious medical emergency.
They are managed slightly differently from a typical heart attack, usually with medications and a coronary angiography to identify any blocked blood vessels that may need treating.
This type of study is a good way of investigating whether the best care is being provided to people with this type of heart attack.
But as the data collected in this registry was not specifically for the study, it is possible that it is not entirely fit for purpose – not all relevant detail may have been recorded, for example – and so may introduce bias.
What did the research involve?
The researchers used European Society of Cardiology guidelines for the management of NSTEMIs and mapped this to UK registry data to see whether guideline-indicated interventions were being followed.
The registry data included adults admitted to one of 247 hospitals in England and Wales with an NSTEMI attack between January 1 2003 and June 30 2013.
NSTEMI cases were identified using the recorded hospital discharge diagnosis. Exclusions were those who died in hospital, where pharmacological therapies were uncertain, or if there was missing data on death.
The data contained information corresponding to 13 interventions, some of which were:
- electrocardiogram (ECG)
- blood pressure medications – such as beta-blockers and ACE inhibitors
- anti-clotting medications – grouped as P2Y12 inhibitors in this study
- advice to quit smoking
- dietary advice
- cardiac rehabilitation programme
What were the basic results?
A total of 389,057 adults were included in the analysis, with an average age of 70.9 years. Researchers found 86.9% were not recorded as receiving one or more recommended interventions.
Some of the ones frequently missed were:
- advice to quit smoking (87.9%)
- dietary advice (68.1%)
- P2Y12 inhibitors (66.3%)
- coronary angiography (43.4%)
Of the missed interventions, the ones estimated to have the strongest effect on reducing survival were:
- coronary angiography
- cardiac rehabilitation
- advice to quit smoking
By modelling the collected data, it was found that if all eligible patients in the study had received all of the interventions recommended to them, 32,765 (28.9%) deaths may have been prevented during the 10-year period.
How did the researchers interpret the results?
The researchers concluded that: "The majority of patients hospitalised with NSTEMI missed at least one guideline-indicated intervention for which they were eligible. This was significantly associated with excess mortality.
"Greater attention to the provision of guideline-indicated care for the management of NSTEMI will reduce premature cardiovascular deaths."
This study aimed to investigate whether adults who have had a non-ST elevation (NSTEMI) heart attack were offered all of the guideline-recommended interventions they were eligible for.
The researchers used guidelines set out by the European Society of Cardiology and found almost 87% of patients were not recorded in the registry as receiving one or more of the 13 interventions reviewed.
This study has both strengths and a number of limitations. This is a large dataset that has been designed to assess the quality of care given for this type of heart attack in the UK.
But the findings are limited by a number of factors:
- Findings from data analysis studies are always limited by the possibility that the recording of data was not complete and there may be some misclassification. For example, interventions such as advice for stopping smoking or about diet may have been classified in the registry as cardiac rehabilitation rather than counselling.
- Reasons for not giving interventions such as contraindications for use or patient refusal were recorded in the registry. However, reasons were not given for those simply recorded as not having received the intervention.
- The researchers excluded more than 31,000 people who died in hospital because they had incomplete information on the medications they received, as well as more than 21,000 who had missing mortality data. The missing cases may have pushed the findings in either direction.
- The design of the study is not able to prove cause and effect. There are a number of other factors beyond the recommended interventions that may have an effect on survival.
- Improvements were seen in the interventions offered over the course of the study – if we are just considering present day data, the picture may therefore be quite different.
- Perhaps most importantly, it is unclear why the researchers compared UK practice against the European Society of Cardiology guidelines, rather than the guidelines on management of NSTEMI issued by the UK guideline body, the National Institute for Health and Care Excellence (NICE). This may have given slightly different results.
Guideline -ecommended interventions for managing heart attacks are usually backed by good-quality research. It is important that the best care is offered to all people, regardless of hospital trust or the severity of their illness.
If you have had this or another type of heart attack, you should take all medicines as prescribed and follow the advice given by your doctors.
Steps to take yourself include making lifestyle changes such as having a healthy diet, maintaining a healthy weight, taking regular physical exercise within your limits, and stopping smoking.