Retrospective 253 hospitalized patients in Israel showing higher mortality and higher risk of severe cases with vitamin D deficiency. Vitamin D levels were measured 14 to 730 days before the COVID-19 test. Adjusted results are only provided for severity.
Dror et al., 6/7/2021, retrospective, Israel, Middle East, preprint, 18 authors.
risk of severe or critical case, 85.1% lower, RR 0.15, p < 0.001, high D levels 109 of 120 (90.8%), low D levels 76 of 133 (57.1%), odds ratio converted to relative risk, >40ng/mL vs. <20ng/mL, multivariate 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.