Retrospective 255 mechanical ventilation patients in USA, showing that weight-adjusted HCQ+AZ improved survival by over 100%. QTc prolongation did not correlate with cumulative HCQ dose or HCQ serum level.
Although authors mention immortal time bias, full details on the timing of HCQ administration is not provided and this is not fully addressed. Survival curves indicate immortal time bias will significantly change results, although the observed benefit appears to exceed the potential bias.
Smith et al., 5/31/2021, retrospective, USA, North America, preprint, 4 authors.
risk of death, 27.2% lower, RR 0.73, p < 0.001, treatment 19 of 37 (51.4%), control 182 of 218 (83.5%), odds ratio converted to relative risk, >3g HCQ and >1g AZ, multivariable cox proportional hazard regression.
risk of death, 92.9% lower, RR 0.07, p < 0.001, ≥80mg/kg HCQ and >1g AZ, RR approximated with OR.
This study is excluded in the after exclusion results of meta analysis: immortal time bias may significantly affect results.
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.