Patients with high blood pressure more likely to be hospitalised or die from Covid-19, Cambridge study finds

People with high blood pressure are more likely to be admitted to hospital or die from Covid-19, regardless of other factors such as age, sex, ethnicity or BMI, a study led by Addenbrooke’s Hospital and the University of Cambridge has revealed.

It is the first study to show the extent of the link and also showed that the type of medication people were receiving to treat high blood pressure - known as hypertension - did not appear to modify the risk.

Those patients whose blood pressure is poorly controlled and above targets were more at risk of dying or being hospitalised.

Since hypertension is more common in ethnic minority and low-income individuals, and rates of control poorer, the study may help explain why these groups are disproportionately affected by Covid.

Lead author Holly Pavey, a British Heart Foundation (BHF) funded PhD student at the University of Cambridge, said: “Before this research, it wasn’t clear to what extent high blood pressure was putting patients at greater risk of hospitalisation or dying from Covid-19.

“Other factors such as age, socio-economic status, sex, ethnicity and BMI were all in the frame too as increasing the risk of severe Covid-19.

“By using data from many thousands of UK volunteers, we found that in individuals who tested positive for Covid-19, those with high blood pressure had a 22 per cent higher risk of being hospitalised or dying from the virus, compared to those without high blood pressure. This risk was almost doubled for those with poorly controlled blood pressure.”

The research was supported by the NIHR Cambridge Biomedical Research Centre and data from more than 16,000 individuals who had tested positive for Covid and who are part of the UK Biobank, a database featuring information from half a million UK volunteers.

Data from up until early 2021 was analysed, helping to reduce any bias from newer, more transmissible variants, and cutting any bias from the effects of widespread vaccinations.

Since the UK Biobank volunteer population is generally healthier than the general UK population, and has relatively few participants from ethnic minority groups, the researchers did urge some caution about generalisations.

Senior author Ian Wilkinson, a cardiology consultant at Cambridge University Hospitals NHS Foundation Trust (CUH) and professor of therapeutics at the University of Cambridge, said: “Hypertension remains the leading risk factor for death in the UK and worldwide, despite effective treatments, and disproportionately affects low income groups and individuals from ethnic minority backgrounds.

“Our findings further emphasise the importance of adequate blood pressure control. Unfortunately, post-pandemic, the rates of blood pressure control have worsened, as have the number of people being screened and identified as having high blood pressure. This is now a major public health problem in the UK and needs to be addressed as part of the levelling-up agenda”.

A national trial is under way to improve treatments for hypertension for people from black, Asian and minority ethnic communities, since most treatments have so far been tested mainly on white people and it is not known if these are as effective on other ethnic groups.

The AIM HY trial is led by Prof Wilkinson with Phil Chowienczyk, professor of clinical cardiovascular pharmacology at King’s College London and chief investigator for the trial.

Prof Chowienczyk said: “These findings highlight the importance of good blood pressure control, especially in individuals disproportionately affected by high blood pressure and Covid-19, such as those in ethnic minority groups in the UK. The AIM HY_INFORM trial is a major study, funded by the BHF and Medical Research Council, that will determine which drugs are most effective at lowering blood pressure in ethnic minority groups in the UK. This should report at the end of 2023 and will be instrumental in shaping new guidelines for the treatment of hypertension in the UK.”

One in three people in the UK have high blood pressure. There are believed to be five million people with undiagnosed hypertension.

Worldwide, it kills more than 10 million people every year.