The effect of l-arginine supplementation on amelioration of oxygen support in severe COVID-19 pneumonia

Background & aims: l-Arginine (l-Arg) has been shown to help reduce respiratory support requirements in coronavirus disease 2019 (COVID-19), in an Italian study. We investigated the effect of l-Arg supplementation on the reduction in respiratory support for patients with severe COVID-19 pneumonia in an Indian population.

Methods: A parallel-group, triple-blinded, randomized controlled trial (RCT) was conducted on patients with severe COVID-19 pneumonia on oxygen (O₂) support. Patients received either 3 g of oral l-Arg or placebo, daily under supervision, until they were off O₂ support, or for a maximum of 10 days, whichever was earlier. The primary outcome was cessation in O₂ support. Other outcomes were time to cessation of O₂ support, duration of hospitalization, and incidence of adverse thrombotic events.

Results: We did an intention-to-treat analysis on 74 patients who were randomized into l-Arg (n = 38) or placebo group (n = 36). There were no significant differences between the two groups in the outcomes. At end of the study, 28 patients (73.6%) in l-Arg and 26 patients (72.2%) in the placebo group were weaned off oxygen support. The median number of days to the cessation of O₂ support estimated using Kaplan Meir survival analysis, was 3 days in the l-Arg group (95% confidence interval [CI]: 1.2, 4.7) and 5 days in the placebo group (95% CI, 4.1,5.8); P = 0.27.

Conclusion: In this group of patients with severe COVID-19 pneumonia, l-Arg supplementation did not show any significant difference in outcomes when compared to placebo supplementation.