Efficiency of Nicotinamide-based Supportive Therapy in Lymphopenia for Patients With COVID-19: A Randomized Controlled Trial
Abstract Background: The purpose of this study was to investigate the efficiency of nicotinamide-based supportive therapy in lymphopenia for patients with coronavirus disease-2019 (COVID-19). Methods: 24 patients diagnosed with the COVID-19 were randomly divided into two groups (n=12) during hospitalization in the ratio of 1:1. Based on the conventional treatment, the treatment group was given 100mg nicotinamide, five times a day. The control group only received routine treatments. The primary endpoint was the change in absolute lymphocyte counts. The secondary endpoints included both the in-hospital death and the composite endpoint of aggravation, according to upgraded oxygen therapy, improvement of nursing level, and ward rounds of superior physicians for changes of conditions. Results: The full blood counts before and after receiving the nicotinamide were comparable in each group (all P>0.05). Before and after receiving the nicotinamide, mean absolute lymphocyte counts were similar between the two groups ([0.94±0.26]*109/L versus [0.89±0.19]*109/L, P=0.565; [1.15±0.48]*109/L versus [1.02±0.28]*109/L, P=0.445, respectively). Therefore, there was no statistically significant difference in the lymphocyte improvement rate between the two groups (23.08±46.10 versus 16.52±24.10, P=0.67). There was also no statistically significant difference for the secondary endpoints between the two groups.Conclusion: Among patients with COVID-19, there was no statistically significant difference in change of full blood counts and the absolute lymphocyte counts before and after intervention in both groups. Therefore, no new evidence was found for the effect of niacinamide on lymphopenia in patients with COVID-19.Trial registration: ClinicalTrials.gov, NCT04910230. Registered 1 June 2021-retrospectively registered.