Women who received prescriptions for hormone replacement therapy (HRT) with estrogen within 6 months of a COVID-19 diagnosis had reduced mortality, according to a new study in Family Practice.
The findings, coupled with data on sex differences between male and female COVID-19 severity, suggest estrogen may have a protective role against the virus.
The study was based on medical records gathered from the Oxford-Royal College of General Practitioners Research and Surveillance Centre primary care database. Researchers looked at women ages 18 and older who received prescriptions for HRT or combined oral contraceptive pill, which contains estrogen.
A total of 1,863,478 women from 465 general practices in England were included in the study. The main outcome was mortality among those with confirmed COVID-19 during the first 6 months of the pandemic in 2020.
Researchers found 5,451 COVID-19 cases within the cohort. White women made up 64.5% of the case-patients, and the mean age was 59. There were 235 women with HRT prescriptions and 171 with a prescription for oral contraceptives. Women with oral contraceptive prescriptions reported no events for all-cause mortality.
Among women with HRT prescriptions, there was a 78% reduction in all-cause mortality in COVID-19 (adjusted odds ratio [OR] 0.22; 95% confidence interval [CI], 0.05 to 0.94).
The all-cause mortality risk in COVID-19 was higher among women who were older, underweight, from larger households, or on immunosuppressant therapies, or who had high blood pressure, the authors said.
COVID patients should not stop HRT
The authors of the study said the findings provide strong evidence for women prescribed HRT to stay on their medication after COVID-19 diagnosis. They also said the findings suggest estrogen products require further investigation as a treatment for the novel coronavirus.
Notably, the study was conducted in the pre-vaccination era of the pandemic, and the authors said further research should continue to look at estrogen levels and COVID-19 severity.
"This study supports the theory that estrogen may offer some protection against severe COVID-19," Christopher Wilcox, PhD, one of the paper's authors, said in a press release. "We hope that this study can provide reassurance to patients and clinicians that there is no indication to stop hormone replacement therapy because of the pandemic."