Women receive unequal treatment after myocardial infarction, Scottish study finds

2nd January 2025

Women in Scotland were undertreated compared to men after a myocardial infarction, with the odds of receiving medicines that can prevent another myocardial infarction ‘stacked against you’ if you are female, researchers suggest.

The first national study in Scotland to examine the difference in treatment and outcomes between the sexes found that women are less likely to receive medicines that can prevent future myocardial infarction, strokes and cardiovascular complications.

The findings are published in the European Journal of Preventive Cardiology and build on an earlier study by the same authors, which found that following a diagnosis of heart disease, the death rate from cardiovascular causes for women increased relative to that of men.

Myocardial infarction is a leading cause of death and disability around the world, affecting men and women differently. The overall association between a person‘s sex and myocardial infarction outcomes is unclear and could be related to different treatment practices between the sexes in healthcare systems.

The researchers examined the treatment and outcome of 15,776 women and 31,287 men admitted to hospital after a myocardial infarction across Scotland between 2010 and 2016. Outcomes in the hospital were analysed according to rates of percutaneous coronary intervention, secondary prevention and mortality.

Each patient was followed for an average of eight years post-hospital discharge until the end of 2021, and rates of cardiovascular mortality and new cardiovascular events were monitored.

The researchers compared the findings to 81,341 matched healthy people without heart disease.

The study found that women were 13% less likely to undergo percutaneous coronary intervention and 6% less likely to undergo cardiac catheterisation than men whilst they were in hospital. Women were also 9% less likely to receive preventative treatments such as statins, beta-blockers or antiplatelets over the follow-up period.

Overall, female patients had lower long-term death rates in comparison to men, but the ‘female survival advantage’ – an observation in which women usually live longer than men – was less pronounced in the people with myocardial infarction.

The researchers found no significant differences in areas across Scotland, but sex differences were more pronounced in deprived areas.

Dr Tiberiu Pana, honorary early career clinical research fellow at the University of Aberdeen, who led the study, said: ‘Our results confirm the presence of important sex differences amongst Scottish heart attack patients. This important finding should guide patients and doctors to work together to improve prescription uptake and compliance with recommended preventative treatments to reduce the burden of heart disease in our population.

Dr Pana emphasised the need to improve the long-term outcomes of women after myocardial infarction, but the researchers also found that treatment for men could also be improved.

Dr Sonya Babu-Narayan, clinical director at the British Heart Foundation and consultant cardiologist, said it was important that existing evidence-based treatments reach both men and women.

But, she added: ‘Time and time again, data show that the odds of receiving medicines that can prevent another heart attack, or a future stroke appear stacked against you if you are a woman. Solving why, including by redressing system and society biases, could help more women in Scotland and other countries live in good health for longer.’

In May 2024, a study revealed that cholesterol-lowering drugs are less frequently prescribed to women compared to men, despite European Society of Cardiology guidelines recommending statins for all patients with chronic coronary syndrome.

A version of this article was originally published by our sister publication Nursing in Practice.

Oxford vaccine protection against severe COVID-19 wanes three months after second dose

22nd December 2021

The Oxford vaccine protection against severe COVID-19 wanes three months after the second dose highlighting the importance of a booster dose

Protection against severe COVID-19 from the Oxford vaccine (ChAdOx1) appears to wane as early as three months after the second dose according to a study by researchers from the MRC/CSO Social and Public Health Sciences Unit, University of Glasgow, UK.

Clinical trial data have shown that the currently available COVID-19 vaccines including ChAdOx1 provide a high level of protection against infection, however, evidence began to emerge of an increased incidence of infection among those who had been fully vaccinated. It was suggested that this might be due to either a waning of vaccine effectiveness or an increase in the dominance of new variants capable of immune escape. However, other data gathered over a 6 month period using the BNT162b2 vaccine found that its efficacy gradually reduced over this period of time.

For the present study, the UK team turned to data from Scotland and Brazil to examine the association between the time since the second vaccination with the Oxford vaccine (ChAdOx1) and the risk of severe COVID-19 outcomes. They chose Scotland and Brazil for comparative purposes because the Delta COVID-19 variant was the dominant strain in Scotland, whereas this was uncommon in Brazil. Consequently, if vaccine effectiveness reduced in both countries this would be unlikely to be because of the delta variant.

Using a retrospective design, the researchers linked data from the EAVE II study which provides COVID-19 data from 5.4 million people in Scotland and databases in Brazil to determine rates of infection, hospitalisation and deaths. They identified individuals from both countries aged 18 years and over who had received two doses of ChAdOx1 and set the primary outcome as the rate of severe COVID-19 outcomes, i.e., hospital admission or death, approximately two to three weeks after the second dose.

Findings

A total of 1972454 adults in Scotland and 42558839 in Brazil received two doses of ChAdOx1. However, an estimate of the vaccine effectiveness was based on a smaller cohort of 2534527 individuals with a mean age of 52 (49.9% male) in Scotland and 56013638 individuals in Brazil with a mean age of 48 years (47% male).

In Scotland the relative risk (RR) of severe COVID-19 was 2.01 (95% CI 1.54 – 2.62) 10 – 11 weeks after the second dose and increased further to 3.01 (after 14 – 15 weeks) and to 5.43 (after 18 – 19 weeks) compared with 2 – 3 weeks after the second dose. In Brazil there was a similar pattern at each time point, for example, the RR was 4.71 after 18 to 19 weeks.

The effectiveness of ChAdOx1 in Scotland decreased from 83.7% (95% CI 79.7 – 87) at weeks 2 – 3 to 63.7% (weeks 18 to 19). Similarly in Brazil vaccine efficacy reduced from 86.4% (2 – 3 weeks after second dose) to 42.2% (weeks 18 to 19).

Commenting on these findings, the authors noted how the similar drop in vaccine effectiveness was unlikely to be due to differences in circulating strains of the virus. They concluded on how these findings clearly illustrate how vaccine effectiveness reduces over time, highlighting the need for a booster vaccination dose.

Citation

Katikireddi SV et al. Two-dose ChAdOx1 nCoV-19 vaccine protection against COVID-19 hospital admissions and deaths over time: a retrospective, population-based cohort study in Scotland and Brazil. Lancet 2021