RCT with 501 relatively low-risk outpatients in Argentina showing hospitalization OR 0.65 [0.32-1.31]. With only 7% hospitalization, the trial is underpowered. The trial primarily includes low-risk patients that recover quickly without treatment, leaving minimal room for improvement with treatment. 74 patients had symptoms for >= 7 days and more than 25% of patients were hospitalized within 1 day (Figure S2). Among the 7 patients requiring ventilation, authors note that the earlier requirement in the ivermectin group may be due to those patients having higher severity at baseline. However, authors know the answer to this - it is unclear why it is not reported. There were more adverse events in the placebo group than the ivermectin group, suggesting a possible issue with dispensing or non-trial medication usage.
Authors pre-specify multivariate analysis but do not present it, claiming "no significant differences in the univariate analysis", however multivariate analysis could significantly change the results. Consider for example if just a few extra patients in the ivermectin group were in severe condition based on baseline SpO2
. The lower mean SpO2
in the ivermectin group, and the shorter time to ventilation, are consistent with this being the case. Additionally, there are 14% more male patients in the ivermectin group.
An extremely large percentage of patients (55%) were excluded based on ivermectin use in the last 7 days. However, ivermectin may retain efficacy much longer (for example antiparasitic activity may persist for months ). A significant number of patients may also misrepresent their prior and future usage - the population is clearly aware of ivermectin, and patients with progressing disease may be motivated to take it, predicting that they are in the control group.
There were no serious adverse events. NCT04529525
Vallejos et al., 7/2/2021, Double Blind Randomized Controlled Trial, Argentina, South America, peer-reviewed, 29 authors, dosage 12mg days 1-2, <80kg 12mg, 80-110kg 18mg, >110kg 24mg.
risk of death, 33.5% higher, RR 1.33, p = 0.70, treatment 4 of 250 (1.6%), control 3 of 251 (1.2%), odds ratio converted to relative risk.
risk of mechanical ventilation, 33.5% higher, RR 1.33, p = 0.70, treatment 4 of 250 (1.6%), control 3 of 251 (1.2%), odds ratio converted to relative risk.
risk of hospitalization, 33.0% lower, RR 0.67, p = 0.23, treatment 14 of 250 (5.6%), control 21 of 251 (8.4%), odds ratio converted to relative risk.
risk of no virological cure, 5.0% higher, RR 1.05, p = 0.55, treatment 137 of 250 (54.8%), control 131 of 251 (52.2%), odds ratio converted to relative risk, day 3.
risk of no virological cure, 26.8% higher, RR 1.27, p = 0.29, treatment 38 of 250 (15.2%), control 30 of 251 (12.0%), odds ratio converted to relative risk, day 12.
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.