Vitamin D and zinc supplementation to improve treatment outcomes among COVID-19 patients in India: results from a double-blind randomized placebo-controlled trial

Early terminated factorial RCT with 46 vitamin D, 48 zinc, 44 vitamin D + zinc, and 43 placebo patients in India.The most serious outcome (ventilation) numbers do not seem realistic. Authors do not specify outcomes per group, but with one event for non-zinc, we know that either the vitamin D only or the placebo group had zero events, which does not match the reported RRs. All 7 RRs are close to 1.0: for D vs. non-D, Z vs. non-Z, D+Z vs. placebo, D vs. placebo, Z vs. placebo, D<20ng/mL vs. non-D, and D>20ng/mL vs. non-D. This suggests unreliable data or analysis (e.g., inappropriate use of Poisson regression). We will update when authors respond.The trial is also unusual in that the primary analyses are unadjusted and compare one treatment with a combination of another treatment and placebo.There are very large baseline differences, e.g., 35 vs. 15% 60+ for zinc vs. non-zinc. There was only 181 patients recruited from 700 planned.There is limited room for improvement with the population studied that recovered very quickly within a median of 3 days. Oral cholecalciferol takes 3-7 days for complete conversion into the biologically active 1,25-dihydroxyvitamin D. Authors could have provided treatment with much faster onset of action, e.g., using calcitriol.There was very little improvement in D/zinc levels with the administration used and the baseline deficiency levels. Only 4% of people went from zinc deficient to sufficient, and only 8% went from vitamin D <30ng/mL to >30ng/mL, and most or all of these improvements may have been after patients already recovered.Notwithstanding the limitations above, we note that, while small, the effect for most outcomes is positive for vitamin D and zinc, and in most cases, the effect in the combined vitamin D + zinc group is larger.Data for this study is not available.