Retrospective 71 chronic HCQ patients compared with 191 matched controls, analyzing only those with a highly suspected or confirmed diagnosis of COVID-19. No significant difference was found in outcomes, however matching failed with extreme confounding - 77.5% of HCQ patients with systemic autoimmune diseases vs. 21.5% of control patients.
Other research shows that the risk of COVID-19 for systemic autoimmune disease patients is much higher overall, Ferri et al. show OR 4.42, p
Trefond et al., 1/27/2021, retrospective, France, Europe, preprint, 21 authors.
risk of death, 16.6% higher, RR 1.17, p = 0.80, treatment 4 of 68 (5.9%), control 12 of 183 (6.6%), adjusted per study, odds ratio converted to relative risk.
risk of combined death/ICU, 78.2% higher, RR 1.78, p = 0.21, treatment 8 of 71 (11.3%), control 18 of 191 (9.4%), adjusted per study, odds ratio converted to relative risk.
risk of hospitalization, 44.9% higher, RR 1.45, p = 0.12, treatment 24 of 71 (33.8%), control 53 of 191 (27.7%), adjusted per study, odds ratio converted to relative risk.
Effect extraction follows pre-specified rules
prioritizing more serious outcomes. For an individual study the most serious
outcome may have a smaller number of events and lower statistical signficance,
however this provides the strongest evidence for the most serious outcomes
when combining the results of many trials.