Adjunct ascorbic acid suppresses thrombosis in critical COVID-19

Low-dose ascorbic acid as an adjunct treatment for the coronavirus disease 2019 (COVID-19) seems to lower the incidence of thrombosis but has no clear impact on mortality, a recent study has found.

Researchers conducted a two-centre, noninterventional, retrospective cohort study including 739 critically ill adult patients with confirmed COVID-19 admitted to the intensive care unit. The primary endpoint was in-hospital mortality, compared between patients who did vs did not receive adjunctive ascorbic acid. Other outcomes included length of stay (LOS), mechanical ventilation (MV) duration, and complications such as acute kidney injury, thrombosis, and respiratory failure.

A total of 158 patients (21.3 percent) were given ascorbic acid treatment, while the remaining 581 (78.7 percent) were not. Before propensity score matching, in-hospital mortality rates were significantly lower in the ascorbic acid group (33.6 percent vs 49.3 percent; p=0.0006) but was attenuated after matching for baseline severity scores, study location, and systematic use of corticosteroids (p=0.11).

Propensity score-adjusted logistic regression analysis confirmed that the risk of in-hospital mortality was comparable between those given ascorbic acid and those not (odds ratio [OR], 0.77, 95 percent confidence interval [CI], 0.476–1.234; p=0.27). The same was true for 30-day mortality (p=0.21).

In terms of complications, thrombosis/infarction occurred significantly less frequently in patients treated with ascorbic acid (6.1 percent vs 13 percent; OR, 0.42, 95 percent CI, 0.184–0.937; p=0.03). No such effect was reported for the other complications assessed.

“Our study shows that a low supplemental dose of enteral ascorbic acid resulted in a significant reduction in thrombosis risk during ICU stay. The underlying benefit of ascorbic acid on thrombosis could be due to its anti-inflammatory properties,” the researchers said. “Further studies are warranted to confirm these findings.”