Limited efficacy of low-dose dexamethasone for the treatment of severe COVID-19 pneumonia: A retrospective study

Abstract

Background: Coronavirus disease 2019 (COVID-19) is caused by severe acute respiratory syndrome coronavirus 2. Its symptoms range from mild to severe, with the latter often being life-threatening. This study aims to assess the effects of low-dose dexamethasone (DEX) in mild-to-severe COVID-19 pneumonia and examine the final clinical outcomes to identify the optimal therapeutic dose.

Methods: Clinical data from 132 patients hospitalized for COVID-19 pneumonia between January and October 2021 at Yamato Municipal Hospital were retrospectively analyzed. Based on the ratio of peripheral arterial oxygen saturation (SpO₂) to inspired fraction of oxygen (FiO₂), patients were categorized into the mild (>450, n = 65), moderate (315-450, n = 55), and severe (<315, n = 12) pneumonia groups. The event of interest was defined as the worsening of the patient's condition during treatment (need to increase FiO₂ > 0.1). Patients were treated with low-dose DEX (6.6 mg/day) for 10 days.

Results: The event-free survival rate decreased significantly in patients with severe pneumonia compared with in those with mild and moderate pneumonia (Bonferroni-adjusted p < 0.02). A total of 16 patients were treated with high-dose corticosteroids because of severe hypoxia. Recovery was observed in all discharged patients with respiratory condition improvement. Low SpO₂/FiO₂ at admission was significantly associated with serum C-reactive protein levels.

Conclusions: For Japanese patients with COVID-19, severe pneumonia, and SpO₂/FiO₂ of <315, it may be necessary to administer a dose of corticosteroids of >6.6 mg DEX.

Keywords: Adaptive dose-finding study; Low-dose dexamethasone; SARS-CoV-2; Severe COVID-19 pneumonia.