Retrospective 510 patients in Iran, showing lower risk of severity with vitamin D (statistically significant) and zinc (not statistically significant) supplementation. IR.TUMS.VCR.REC.1398.1063.
Bagheri et al., 9/1/2021, retrospective, Iran, Middle East, peer-reviewed, 6 authors, dosage not specified.
risk of disease progression, 70.9% lower, RR 0.29, p = 0.02, treatment 131, control 379, adjusted per study, multinomial logistic regression, RR approximated with OR.
risk of being in the hospitalized vs. outpatient group, 37.9% lower, RR 0.62, p = 0.11, treatment 28 of 131 (21.4%), control 143 of 379 (37.7%), adjusted per study, odds ratio converted to relative risk, binary logistic regression.
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.