Retrospective 27 severe COVID-19 patients and 23 non-COVID-19 patients, showing signifcantly lower vitamin A levels in COVID-19 patients (0.37mg/L vs. 0.52 mg/L, p
<0.001). 10 of 27 COVID-19 patients received vitamin A, with higher mortality. Group details are not provided but authors note that 8 of 10 had comorbidities.
Sarohan et al., 2/1/2021, retrospective, Turkey, Europe, preprint, 4 authors.
risk of death, 282.5% higher, RR 3.83, p = 0.001, treatment 9 of 10 (90.0%), control 4 of 17 (23.5%).
This study is excluded in the after exclusion results of meta analysis: unadjusted results with no group details.
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.