Malaria drugs pushed by President Donald Trump as treatments for the coronavirus did not help and were tied to a greater risk of death and heart rhythm problems in a new study of nearly 100,000 patients around the world.

Friday's report in the journal Lancet is not a rigorous test of hydroxychloroquine or chloroquine, but it is by far the largest look at their use in real world settings, spanning 671 hospitals on six continents.

"Not only is there no benefit, but we saw a very consistent signal of harm," said one study leader, Dr. Mandeep Mehra, a heart specialist at Brigham and Women's Hospit...