Full doses of blood thinners can benefit patients hospitalized with COVID-19, but the severity of their illness matters, researchers say.

The new global analysis found that hospitalized patients with moderate COVID-19 may benefit from the drugs’ clot-preventing powers, but patients with illness so severe it requires admission to an intensive care unit may not.

“SARS-CoV-2 infection can increase the risk for developing blood clots by causing a significant inflammatory response in the body,” explained Dr. Aeshita Dwivedi, a cardiologist at Lenox Hill Hospital in New York City.

“These blood clots can further lead to debilitating and life-threatening conditions like heart attacks, strokes or pulmonary embolisms,” said Dwivedi, who wasn’t involved in the new study.

She said the new data “has demonstrated that a higher dose of blood thinners, in addition to being safe, reduced the need for life support and possibly even death” in moderately ill patients in the hospital.

Early in the COVID-19 pandemic, doctors worldwide noted that COVID-19 patients had high rates of blood clots and inflammation that led to complications, such as lung failure, heart attack and stroke. At the time, it wasn’t known whether providing COVID-19 patients with high doses of blood thinners would be safe and effective.

Last December, the same group of researchers released findings showing that routine use of full-dose blood thinners in more critically ill COVID-19 patients was not beneficial, and may even have been harmful in some cases.

But what about the drugs’ effect in moderately ill patients?

“To meet the challenge of this pandemic, investigators worldwide joined forces to answer this question as rapidly as possible,” according to a news release from the U.S. National Heart, Lung, and Blood Institute (NHLBI). The institute partnered with similar agencies in Canada, the United Kingdom and Australia to help produce this research, which involved more than 300 hospitals worldwide.

Researchers assessed whether full doses of the blood thinner heparin were more beneficial for more than 1,000 moderately ill hospitalized adults with COVID-19 than the lower doses typically used to prevent blood clots.

Moderately ill patients were defined as people who weren’t in intensive care and did not require organ support, such as mechanical ventilation.

Preliminary findings from the trials showed that full-dose blood thinners were safe, lowered the need for life support, improved outcomes for moderately ill patients and may have reduced their risk of death. The latter finding does require further study, the NHLBI said.

Large numbers of COVID-19 patients have to be hospitalized, but these findings suggest that the use of full-dose blood thinners could reduce the strain on intensive care units worldwide.

The researchers said they are now moving as fast as possible to make the full results of the trials available to help doctors make informed decisions about treating hospitalized COVID-19 patients.

For her part, Dwivedi stressed that the analysis is still preliminary.

“While these results offer hope, they should not influence current clinical practice until the data is fully analyzed and subjected to rigorous peer review,” she said. “More than 20 studies are being conducted worldwide to answer this question. If the studies consistently mirror the preliminary results, it would add another useful tool in the currently limited armamentarium for the treatment of COVID-19.”

More information

The U.S. Centers for Disease Control and Prevention has more on COVID-19.

SOURCES: Aeshita Dwivedi, MD, cardiologist, Lenox Hill Hospital, New York City; U.S. National Heart, Lung, and Blood Institute, news release, Jan. 22, 2021