Small retrospective study with 63 patients (32 treated with HCQ), showing no effectiveness, however the baseline state of each arm significantly differs.
This preprint was submitted to NEJM but has not been published several months later.
Barbosa et al., 4/12/2020, retrospective, USA, North America, preprint, 5 authors.
risk of death, 147.0% higher, RR 2.47, p = 0.58, treatment 2 of 17 (11.8%), control 1 of 21 (4.8%).