Men with low testosterone levels have a much higher risk of severe illness and death from COVID-19, a new study from Italy finds.
The study included nearly 300 symptomatic male COVID-19 patients who arrived at the emergency department and were admitted to San Raffaele University Hospital in Milan during the first wave of the pandemic.
The lower the patients' levels of the hormone testosterone, the more likely they were to require intensive care, to be intubated on a ventilator and to have a longer hospital stay. Patients with low testosterone had a sixfold increased risk of death, the researchers reported.
The results were scheduled for presentation at the virtual European Association of Urology Congress, held July 8 through 12.
"At the start of the COVID pandemic, we were seeing far more men than women coming to hospital and suffering very severe forms of the disease. We immediately thought this might be related to male hormone levels, particularly testosterone," said study author Andrea Salonia, a specialist in urology and endocrinology at San Raffaele Hospital.
"But we never expected to see such a high proportion of COVID patients with these extremely low levels of testosterone, in comparison to a similar group of healthy men. The relationship is very clear: The lower the testosterone, the higher the severity of the condition and likelihood of death. I've never seen anything like it in my 25 years in the field," Salonia said in an association news release.
Nearly 90% of the patients in the study had low testosterone levels (9.2 nanomoles per liter [nmol/L] or less), compared with only 17% of 305 healthy men who acted as a control group. Testosterone levels in the COVID-19 patients averaged around 2.5 nmol/L.
Patients with mild symptoms and those who didn't require intensive care had slightly higher testosterone levels (between 3 and 4 nmol/L) than those admitted to the intensive care unit or those who died of the disease (0.7 to 1.0 nmol/L).
Even when the researchers accounted for age, pre-existing health conditions and weight, there were still significant differences in testosterone levels and outcomes among the patients, according to the study.
The researchers didn't have data on the COVID-19 patients' testosterone levels before they contracted the disease, so they couldn't determine whether low testosterone was a pre-existing condition that made the disease worse or whether the coronavirus infection caused low testosterone.
"We simply don't have the data to know which came first in these patients, the low testosterone levels or the COVID," Salonia said.
"Testosterone does play a role in protecting men from disease. However, it's also possible that the virus itself is able to induce an acute reduction in testosterone levels, which then predisposes these men to a worse outcome," Salonia added. "We're now following up these patients over a longer time period, to see how their hormone levels change over time, so we can try and answer these questions."
Data and conclusions presented at meetings should be considered preliminary until published in a peer-reviewed medical journal.
The U.S. Centers for Disease Control and Prevention has more on COVID-19.
SOURCE: European Association of Urology Congress, news release, July 7, 2021