(1) Background: Obesity is a risk factor for severe COVID-19 outcomes. Obesity can interfere with the action of vitamin C. The study aimed to investigate the association between BMI and severe outcomes of COVID-19 while considering vitamin C levels; (2) Methods: This was a retrospective study of 63 COVID-19 patients treated at the NMC Royal Hospital, United Arab Emirates; (3) Results: There was no significant difference in vitamin C levels among patients in all BMI categories (p > 0.05). The risk of severe COVID-19 significantly increased by 5.4 times among class 1 obese patients compared with normal BMI (OR = 5.40, 95%CI: (1.54−21.05), p = 0.010). Vitamin C did not affect the risk of COVID-19 severity or mortality across BMI categories (p = 0.177, p > 0.05, respectively). The time till viral clearance was significantly different among patients in different BMI categories when vitamin C levels were considered (p = 0.02). Although there was no significant difference in vitamin C levels across BMI categories, there was a significant interaction between vitamin C levels and viral clearance rate in obese patients; (4) Conclusions: Given the safety of vitamin C supplements and our findings, proper vitamin C uptake and supplementation for patients of various BMI levels are encouraged.
Keywords: COVID-19; body mass index; obesity; severity; viral clearance; vitamin C.