January 19, 2023

expert reaction to study looking at cardiovascular disease prevention and management during the COVID-19 pandemic

A study published in Nature Medicine looks at the impact of the COVID-19 pandemic on cardiovascular disease prevention and management, including how many people missed out on starting medicines for high blood pressure and cholesterol.

Prof Bryan Williams, Chair of Medicine, UCL, said: 

“This is important information, illustrating the research power of the NHS data sets.  The study confirms what many of us have observed clinically in terms of interrupted access to chronic disease management during the pandemic.  This is likely to be a factor contributing to the reported excess deaths in the UK in the past 12 months, especially the less effective treatment of high blood pressure.  However, the link between change in prescribing patterns and outcomes is the weaker aspect of the study.  The reported effect size looks modest but I am not quite so reassured because the reassurance is dependent on the modelling used to estimate the effects of not treating hypertension on outcomes.  In this study it entirely depends on the model used by NICE, projected over a lifetime and are thus not ideal in this context.  What we know from clinical trials is that the benefits of blood pressure lowering on risk of stroke and heart disease differ temporally.  One would expect to see more of an impact of BP reduction on stroke than on risk of myocardial infarction both in terms of speed of effect (very rapid for stroke prevention) and magnitude of effect.  Thus, one would expect more of an impact of not initiating treatment in somebody who needs it, to be noticeable for stroke, versus myocardial infarction because of the relatively short duration of study.   It will also be strongly impacted on by the absolute risk of the patient, largely determined by their age but also their baseline blood pressure and other risk factors and comorbidities. 

“It is well documented that elevated blood pressure contributes to 10 million deaths globally every year, not just in a once in a generation pandemic, but every year.  This data shows the potential impact of the pandemic on disruption to routine disease prevention.  It also emphasises that the model of care needs urgent review.  Patients shouldn’t need to visit doctors to get their blood pressure checked and their treatment dispensed, there are much better and more efficient ways of doing this that would be more convenient and more effective for patients.  Perhaps that is the most important take away from this study.” 

Prof Kevin McConway, Emeritus Professor of Applied Statistics, The Open University, said: 

“This is a thorough and competent piece of work, and it’s important to be aware that the estimates for the numbers of additional CVD events (heart attacks, strokes, heart failure, angina and similar) relate only to people not starting on one of the classes of medication they looked at, antihypertensive drugs.  Including other classes of drugs, would be complicated, as the researchers explain. 

“However, though the numbers of people who would have started on antihypertensive medication, if the rates of starting on it during the pandemic had been as in 2019, look large – almost half a million – the impact of that on health needs some thinking about.  The researchers estimate that, if all these people remain untreated for the rest of their lives, there would be roughly an extra 14,000 cardiovascular disease events in the rest of their lives.  Not 14,000 extra events a year – 14,000 over the rest of their lives.  People newly starting on antihypertensives are not usually young, but many of them would be in late middle age with a lot of years of life left.  And this is also on the assumption that none of them ever go onto antihypertensives after they missed out during the pandemic. 

“14,000 events, of which about 2,300 are heart attacks and 3,500 are strokes, may sound like a lot.  But in 2019/20, the last full year which did not overlap a great deal with the Covid pandemic, the British Heart Foundation report¹ that there were about 203,000 hospitalisations in England, Scotland and Wales for heart attacks, and about 260,000 for strokes.  The latest estimate for new cases of all cardiovascular diseases (for 2019) is that there were about 520,000 in England, Scotland and Wales.  Compared to these very high annual numbers, an extra 14,000 events in total, over lives that may last for several decades, are going to be lost in the noise. 

“What’s more, people’s risk of a CVD event increases with age, other thing being equal, so these numbers spread over lifetimes would increase over time.  The average risks in the first couple of years after not starting on the medication are really not very high.  So extra disease from this cause just can’t be contributing in an important, or even a clearly measurable, way to current numbers of excess deaths.  (And in any case, it’s certainly not the case that everyone who suffers a CVD event will die as an immediate consequence.)  That’s illustrated in another way by a different set of estimates in the research paper – the numbers assuming that the 490,000 who missed out on starting on hypertensives remain untreated for five years, not their whole lives.  On that assumption, there would be just 2,700 extra CVD events – and that’s still over the rest of these people’s lives, even after the 5 years when they are assumed to have started on the drugs (because no drug can entirely prevent cardiovascular disease). 

“I’m certainly not claiming that this research is unimportant.  It does draw attention to an aspect of medical diagnosis and treatment that didn’t happen as much during the pandemic as before, and that issue does need to be dealt with.  Also we’ve got to remember that the position is complicated – other medications were studied in the research, but their effects on CVD events weren’t included in the calculation.  And there’s no consideration of people who would have been advised to make lifestyle changes, such as taking more exercise or changing their diets, if they had had high blood pressure detected during the pandemic.  Some of them would also have had additional CVD events during their lives if they didn’t make the lifestyle changes later.  Cardiovascular disease remains a major cause of ill health and of death in the UK as in many other countries. 

“But, on the other hand, I’d argue that the number of people starting on antihypertensive medication during the pandemic was actually remarkably high, given all the issues of access to health services that we know about.  Before the pandemic, there were over 100,000 people starting on this medication each month in England, Scotland and Wales.  That number was reduced by 27,000 each month, on average, between March 2020 and July 2021.  But that average is taken over 17 months where the reduction in new prescriptions varied a lot from month to month.  At the height of the first lockdown (April-June 2020), and again in January and February 2021, the reduction was very large, with not all that much more than half the usual new treatment starts taking place.  But things weren’t perhaps so bad in other months, despite all the restrictions that were in place for much of that period.  And this study can’t tell us what happened after July 2021.  Have new prescriptions got up to the pre-pandemic levels?  Are we catching up and indeed starting treatment for some of the people who missed out in 2020 and 2021?  If not, action is needed, but there are questions of priority compared to all the other health service issues that are going on.” 

1 British Heart Foundation Heart and Circulatory Disease Statistics 2022, https://www.bhf.org.uk/-/media/files/research/heart-statistics/bhf-statistics-compendium-2022.pdf 

Prof Sir David Spiegelhalter, Emeritus Professor of Statistics, University of Cambridge, said: 

“This excellent study is surprisingly reassuring.  Following the disrupted preventive health care over the pandemic, they predict over 2,000 extra heart attacks and 3,000 extra strokes, which may sound bad, but this assumes the individuals remain untreated and covers their whole lives.  This comes out at perhaps 100 extra heart attacks a year, or 2 a week, which is not a big number, especially when compared to the 100,000 annual hospital admissions for heart attacks reported by the British Heart Foundation.  This study therefore implies that disrupted cardiovascular prevention is playing a negligible role in current excess deaths.” 

‘The impact of the COVID-19 pandemic on cardiovascular disease prevention and management’ by Caroline E. Dale et al. was published in Nature Medicine at 16:00 UK time on Thursday 19 January 2023. 

DOI: 10.1038/s41591-022-02158-7 

Declared interests 

Prof Bryan Williams: “I am President of the International Society of Hypertension and Chair of Medicine UCL.” 

Prof Kevin McConway: “I am a Trustee of the SMC and a member of its Advisory Committee.  My quote above is in my capacity as an independent professional statistician.” 

Prof Sir David Spiegelhalter: “I am a Non-Executive Director of the UK Statistics Authority, which oversees the work of the Office for National Statistics.”