A study of 96,000 hospitalized coronavirus patients on six continents found that those who received an antimalarial drug promoted by President Trump as a “game changer” in the fight against the virus had a significantly higher risk of death compared with those who did not. People treated with hydroxychloroquine, or the closely related drug chloroquine, were also more likely to develop a type of irregular heart rhythm, or arrhythmia, that can lead to sudden cardiac death, it concluded. … For those given hydroxychloroquine, there was a 34 percent increase in risk of mortality and a 137 percent increased risk of a serious heart arrhythmias. For those receiving hydroxychloroquine and an antibiotic — the cocktail endorsed by Trump — there was a 45 percent increased risk of death and a 411 percent increased risk of serious heart arrhythmias.