Treatment of COVID-19 Patients by Glucocorticoids: Which Dose? Which Type? A Single- Center Cohort Study

Abstract Background Glucocorticoids were widely used in COVID-19, but the optimal type and cumulative dose remain unclear, especially regarding short-term outcomes and adverse effects. Objective To investigate the association between cumulative doses of different glucocorticoids (methylprednisolone, dexamethasone, prednisolone) and clinical outcomes (mortality, hospital stay, ICU admission, and lung involvement) in hospitalized COVID-19 patients. Methods This single-center historical cohort study included 5,261 hospitalized patients with confirmed COVID-19 and pulmonary involvement who received at least one glucocorticoid. Cumulative steroid doses (mg) were used as continuous independent variables. Outcomes included in-hospital mortality, length of stay, ICU admission, ICU length of stay, and change in CT severity score (0–25). Multivariable logistic and linear regression models were adjusted for age, sex, baseline SpO₂ (continuous), initial CT score (continuous), and cumulative doses of remdesivir, tocilizumab, and anakinra. To address channeling bias, we performed additional sensitivity analyses, including propensity score matching and E-value calculations. Results Overall mortality was 6.3% in the study cohort. In multivariable analysis, a higher cumulative methylprednisolone dose was independently associated with lower mortality (OR per 100 mg increase: 0.82, 95% CI: 0.74–0.91, p < 0.001). Higher cumulative dexamethasone dose was associated with longer hospital stay (β = 0.68 per 10 mg, p < 0.001) and with less radiological improvement (β = 0.42 per 10 mg, p = 0.031). A higher prednisolone dose was also associated with a longer length of stay (β = 0.29 per 50 mg increase, p = 0.009). No glucocorticoid was independently associated with ICU length of stay after adjustment. The R² values for hospital stay models ranged from 0.18 to 0.31, indicating that steroid dose explained a modest but significant portion of the variance. Conclusion In this observational study, a higher cumulative methylprednisolone dose was associated with reduced mortality, while higher dexamethasone and prednisolone doses were associated with prolonged hospitalization. Given the high risk of channeling bias and time-dependent confounding, these results should be interpreted strictly as hypothesis-generating. They should not be used to guide changes in clinical practice. Future randomized controlled trials directly comparing different glucocorticoid types and doses are urgently needed.