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.
risk of disease progression, 60.4% lower, RR 0.40, p = 0.41, treatment 33, control 477, adjusted per study, multinomial logistic regression, RR approximated with OR.
risk of being in the hospitalized vs. outpatient group, 41.0% lower, RR 0.59, p = 0.37, treatment 4 of 33 (12.1%), control 167 of 477 (35.0%), 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.