May 29 (UPI) -- A high number of patients with severe COVID-19 develop deep vein thrombosis, or dangerous blood clots that can migrate to the lungs, a study published Friday by JAMA Network Open has found.
In addition, despite aggressive therapy with anti-coagulant drugs, 15 percent of patients included in the analysis developed clots within two days of admission to a hospital intensive care unit, the authors observed.
"In view of the high rate of deep vein thrombosis reported in this study, prognosis might be improved with early detection and a prompt start of anticoagulant therapy," researchers at North Cardiological Center in Saint-Denis, France, wrote in the study.
Deep vein thrombosis, or DVT, occurs when a blood clot forms in a "deep" vein -- typically form in the thigh or lower leg. These clots can travel to the arteries in the lungs, causing a condition called pulmonary embolism, the French researchers noted.
Up to one in four people with serious illness from COVID-19, the disease caused by the new coronavirus, SARS-CoV-2, develop a pulmonary embolism, researchers have found. The condition can cause breathing difficulties, low oxygen levels in the blood and lead to death.
For their study, the French researchers reviewed data on 34 COVID-19 patients at their hospital. The patients were, on average, roughly 62 years old.
In all, 15 of the 34 had diabetes and 13 suffered from high blood pressure, the researchers reported. People with these conditions are considered at high risk for serious illness and death from COVID-19.
Only one of the 34 patients was on anti-clotting medication prior to being admitted to the hospital with COVID-19, according to the researchers. Still, 26 were treated with norepinephrine for the management of heart complications related to COVID-19 at hospital admission and 16 required prone positioning -- lying chest down -- for lung or breathing support.
Both steps are recommended by the World Health Organization for adult patients with severe COVID-19.
DVTs were found in 22 patients at admission and in 27 patients, or 79 percent, in venous ultrasonograms performed two days after admission to the ICU. The JAMA Network Open report did not include information on how many of these patients ultimately survived.
"The occurrence of pulmonary embolism might be favored by deep vein thrombosis," the authors wrote. "Systematic anti-coagulant therapy for all ICU patients with COVID-19 should be assessed."