Case control study with 156 PCR+ cases in India and 204 controls, showing more frequent vitamin D deficiency in COVID-19 patients, and an association between lower vitamin D levels and COVID-19 severity.
Nimavat et al., 8/5/2021, retrospective, India, South Asia, peer-reviewed, 5 authors.
risk of death, 50.4% lower, RR 0.50, p = 0.17, high D levels 13 of 131 (9.9%), low D levels 5 of 25 (20.0%), >10ng/mL, within cases.
risk of COVID-19 severe case, 67.6% lower, RR 0.32, p = 0.003, high D levels 17 of 131 (13.0%), low D levels 10 of 25 (40.0%), >10ng/mL, within cases.
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.