Analysis of 20 hospitalized COVID-19 patients, 13 requiring ICU admission. 84.6% of the ICU patients had low vitamin D levels versus 57.1% of the non-ICU patients.
Lau et al., 4/28/2020, retrospective, USA, North America, preprint, 7 authors.
risk of ICU admission, 45.0% lower, RR 0.55, p = 0.29, treatment 2 of 5 (40.0%), control 11 of 15 (73.3%), >30ng/mL.