Introduction

In December 2019, an illness characterized by pneumoniae associated with new coronavirus (COVID-19) emerged in Wuhan, China, and rapidly spread around the world. The World Health Organization had declared South America as an epicenter of COVID-19 pandemic, and Brazil has become one of the most affected countries of the world [1]. The greatest impact of these disease was on Intensive Care Units (ICU), almost 40% of the COVID-19 patients evaluated with acute respiratory failure [2,3]. The mortality of the patients in mechanical ventilation is high, about 88.1%, according to the cohort described by Richardson and colleagues [4-7].

Due to an expressive mortality a lot of therapies emerged to control the disease. One of these therapies was the use of systemic corticosteroids. Over decades, many clinical trials have tested the effectiveness of corticosteroids in critically ill patients with pneumonia, septic shock, or acute respiratory syndrome, however, due to limited sample size, variable dosing strategies and inconsistent findings, results remained inconclusive [8].

Corticosteroids were widely used during outbreaks of Severe Acute Respiratory Syndromes (SARS) like the Middle East Respiratory Syndrome (MERS-CoV) without improvement [9], and in Influenza pneumonia when the use was associated with a higher mortality [10,11].

COVID-19 affects several organs, manly the lung. The pulmonary histology reveals inflammation and diffuse alveolar damage [12,13]. Acute lung injury is partly caused by the host immune responses. Inflammatory organ injury may occur in severe COVID-19, in a subgroup of patients who have high levels of inflammatory markers, including C-reactive protein, ferritin, interleukin-1 and interleukin-6 [14,15]. Several therapeutics have been proposed to mitigate the inflammatory organ injury in viral pneumonia. The corticoids are one of these therapeutics, it can suppress lung inflammation, but it can also inhibit immune responses and pathogen clearance [16,17]. In case of inhibit immune responses some infectious clinical condition may occur, like invasive fungal disease, cytomegalovirus infection, other viral diseases, and bacterial infections [18].

The primary objective of this study was to evaluate the association between the use of systemic methylprednisolone and 28-days all-cause mortality in patients with acute respiratory syndrome caused by COVID-19 on invasive mechanical ventilation. The secondary objectives were length of stay in the intensive care unit, length of stay in the hospital, hospital mortality, duration of mechanical ventilation, number of extubations, number of tracheostomies, ventilator-associated pneumonia and bloodstream infections.

Methods

A unicentric prospective randomized double-blinded study was designed to evaluate if the effectiveness and safety of methylprednisolone associated with the stand of care was superior to stand of care alone for reduction of 28-days mortality in patients with COVID-19 on mechanical ventilation.

Sample size calculation: based on the previous data, Richard et al. [14] showed a hospital mortality of 88.1% of patients with COVID-19 on mechanical ventilation. Wu C, et al. [12] showed a 25.56% mortality reduction in COVID-19 patients treated with methylprednisolone. For the sample calculation, with power of 80% and an α less than 0.05 assumed, a sample of 112 patients were calculated resulting in 56 patients in the intervention group and 56 patients in the control group randomized 1:1.

The inclusion criteria were patients over 18 years old with COVID-19 on invasive mechanical ventilation within 24 hours of meeting criteria of moderate or severe Acute Respiratory Distress Syndrome (ARDS) defined as the ratio of arterial partial pressure of oxygen to fraction of inspired oxygen (PaO2:FIO2) of 200 or less, with positive RT-PCR test for COVID-19 at the time of inclusion.

Exclusion criteria were pregnancy or active lactation, known history of methylprednisolone allergy, corticosteroid use in the past 15 days for no hospitalized patients, use of corticosteroids during the present hospital stay, consent refusal, or expected risk of death in the next 24 hours.

The patients were randomized into two groups 1:1 by the pharmacist responsible for the unit. The others health professionals were blind to the medication administered (methylprednisolone or placebo). The pharmacist was notified of the inclusion of the patient, performed randomization, and delivered the medication (methylprednisolone or placebo) to the ICU staff in an injection bottle with only the identification of the patient. The methylprednisolone group consists of initial dose of 1 mg/Kg/day for five days, followed by 0.5 mg/Kg/day for three days and 0.25 mg/Kg/day for two days. The placebo group received intravenous injection of 0.9% saline associated a stand of care. The saline and methylprednisolone solution were indistinguishable to the naked eye.

Written informed consent was obtained from all patients or from a legal responsible if they were unable to provide one. The trial was conducted in accordance with the principles of Good Clinical Practice Guidelines of International Conference and Helsinki Criteria and was approved by the Ethics Committee of Institute of Medical Assistance to the State Server in São Paulo (IAMSPE)  (CAAE 32561120.6.0000.5463).

The primary outcome was the mortality at 28-days. The secondary outcomes were length of stay in the intensive care unit, length of stay in the hospital, hospital mortality, duration of mechanical ventilation, number of extubations, number of tracheostomies, ventilator-associated pneumonia and bloodstream infections.

Diagnosis of infections were made by the attending physician. For the diagnosis of pneumonia associated with mechanical ventilation it was necessary to have more than 48 hours of mechanical ventilation and 2 of the 3 criteria: increase or change of the color of tracheal secretion, decrease the PaO2/ FIO₂ ratio or positive culture of tracheal secretion with pathogens >105 CFU/mL. Pulmonary imaging was not included, due to the possibility of worsening of the pulmonary image be related to worsening of inflammatory caused by COVID-19. Bloodstream infections was considered if the patient had one or more positive blood culture collected from peripheral blood and the pathogen was not related  to another site of infection.

Patients were followed until the outcome (death or discharge), if the patient was discharged from the hospital before 28 days after randomization, a physician made a telephone contact on the twenty-eighth day after inclusion.

Statistical analyses

The full analysis included all the participants who underwent randomization and received a dose of methylprednisolone or placebo. The analyses were conducted in the per-protocol population, which included participant who received methylprednisolone or placebo.

A preplanned interim analysis for the evaluation of efficacy and safety after 88 patients with full follow-up was scheduled. The stopping rule for safety was p<0.1 and for efficacy p<0.001 (Haybittle-Peto boundary) [19]. There was no adjustment in the final threshold for statistical significance for sequential analysis.

The trial was designed to ascertain whether methylprednisolone reduces the 28-days mortality. The primary comparison between the groups was performed using the X2test. The comparison of the duration of mechanical ventilation, length of stay in the ICU and in the hospital between the two groups was performed using Log Rank test. Adverse events are expressed as counts and percentages and compared between the two groups using the X2-test.

Patients were analyzed according to the randomization groups, and no adjustments for multiplicity were performed. A 2-sided p value of less than 0.05 was considered statistically significant. All analyses were performed using the SPSS software version 24.0.

Results

From July 2020 to March 2021, 148 patients were evaluated in a hospital with medical residence. Of the 148 patients who were screened, 112 underwent randomization, 58 to methylprednisolone group and 54 were assigned to placebo. Two patients (one who was assigned to receive placebo and one who was assigned to receive methylprednisolone) did not received an infusion. One patient was in refractory septic shock and thirty-three without informed consent. The 112 patients who underwent randomization and received at least one infusion of methylprednisolone or placebo were included in the efficacy and safety analyses (Figure 1).

             Figure 1: Flowchart of the study.

Baseline characteristics between the groups showed a higher severity in the placebo group (mean SOFA of 7.24 ±2.41 in placebo group and 6.17 ±2.41 in methylprednisolone group, p = 0.021), there were more patients with systemic arterial hypertension in the methylprednisolone group, 38 (65.5%) vs 25 (46.3%) in placebo group, p=0.04. The other baseline characteristics were well balanced between groups (Table 1).

Table 1: Demographic and baseline characteristics between the two groups

 * BMI – body mass index

 ** COPD - chronic obstructive pulmonary disease

Driving pressure was higher in methylprednisolone group, mean of 11.57 ±2.16 in the methylprednisolone group Vs 10.59 ±2.59 in the placebo group, p=0.037, the other respiratory variables were similar between the groups, there was also no difference between the groups regarding the use of antibiotics and vasopressors (Table 2).

Table 2: Respiratory measures, use of antibiotics and vasopressors between the two groups

*PEEP - positive end-expiratory pressure

** Mean dose of norepinephrine on the first day

Primary Outcome

There was no significant difference in all-cause mortality at 28 days (24.1% in the methylprednisolone group vs 29.6% in the stand of care alone group, p=0.512).

Secondary Outcome

The mean of the number of days in ICU stay was lower in the methylprednisolone group, (12.5 days ±10.45 in the methylprednisolone group vs 18.76 ±15.1 in the placebo group, p=0.043). There was no significant difference between groups with regard length of hospital stay (25.0 ± 18.96 in the methylprednisolone group vs 28.57 ± 20.39 in the placebo group). Although there is no difference between the hospital stay, the discharge rate in the 28 -days was higher in the methylprednisolone group than in the placebo group, (48.3% in the methylprednisolone group vs 27.8% in the placebo group, p=0.026). There was no significant difference in all-cause hospital mortality (32.8% in the methylprednisolone group and 48.1% in the placebo group, p=0.097).

The median of the days in mechanical ventilation was also significant lower in the methylprednisolone group than in the placebo group, 6 days vs 14 days: IC 95%, p = 0.012, (Figure 2).

Figure 2: The median of the days in mechanical ventilation.

There was significant difference in the number of extubated patients (67.2% in the methylprednisolone group vs 48.1% in the placebo group, p=0.042). The number of extubated patients were counted as extubated for the first time with no extubation failure. The number of tracheostomies was lower in the methylprednisolone group, five patients in the methylprednisolone group and fourteen in the group placebo (p=0.015). 

There was no difference in adverse events between the two groups regarding bloodstream infections (10.3% in methylprednisolone group vs 16.7% in placebo group, p=0.326), and pneumonia associated with mechanical ventilation (37.9% in methylprednisolone group vs 51.9% in placebo group, p=0.139). We also did not have any cases of pulmonary aspergillosis due to the use of corticosteroids.