https://reason.com/2020/05/26/hydroxychloroquine-and-chloroquine-increase-covid-19-patients-risk-of-death-says-new-study/

Sadly, accumulating scientific evidence is ever more strongly indicating that the president's hopes for chloroquine and hydroxychloroquine as breakthrough treatments for COVID-19 are not being borne out.

The latest blow to those hopes was a huge observational study published last Friday by researchers in The Lancet. Researchers assessed nearly 100,000 COVID-19 patients from 671 hospitals on six continents with about two-thirds of the patients hailing from North America. They compared those being treated with chloroquine and hydroxychloroquine alone or in combination with the antibiotics azithromycin or clarithromycin with a cohort of patients who did not take those drugs.

The researchers controlled for multiple confounding factors such as age, sex, race or ethnicity, body-mass index, underlying cardiovascular disease and its risk factors, diabetes, underlying lung disease, smoking, immunosuppressed condition, and baseline disease severity.