Efficacy of high-dose intravenous immunoglobulin in severe and critical COVID-19: A retrospective cohort study

BACKGROUND: Various immunomodulatory therapies have been explored to manage the dysregulated immune response seen in severe COVID-19 infection. The objective of this study was to evaluate the efficacy of intravenous immunoglobulin (IVIG) in severe and critical COVID-19 disease. METHODS: This retrospective study included 535 patients with severe and critical COVID-19 admitted to the intensive care unit (ICU) of a tertiary care hospital, from May 2020 to December 2020. Primary outcome was the percentage of patients requiring mechanical ventilation. Secondary outcomes were a) in-hospital mortality, b) 28-day mortality, c) ICU-length of stay (ICU-LOS), d) days to discontinuation of supplemental oxygen, and e) days to COVID-PCR negativity. Logistic regression and linear regression were performed using the adjusted and unadjusted analyses. RESULTS: We analyzed a total of 535 patients out of which 255 (47.7%) received IVIG along with standard treatment and 280 (52.3%) received only standard treatment. Two groups were similar in terms of COVID-19 severity, APACHE II score, oxygen requirements, and initial management. The requirement of invasive ventilation was significantly less in the IVIG group compared to the Non-IVIG group (32.2% vs 40.4%, p < 0.05). In-hospital mortality, 28-day mortality, and ICU-LOS were also significantly less in the IVIG group (all p < 0.05). Subgroup analysis within the IVIG group showed that early administration of IVIG (≤7 days from ICU admission), old age (≥65 years), and obesity were associated with better outcomes (need for mechanical ventilation and in-hospital mortality) (all p < 0.05). IVIG administration in patients with chronic respiratory disease was associated with a reduced requirement for mechanical ventilation (p < 0.05), but there was an insignificant improvement in mortality. CONCLUSION: High-dose IVIG improves outcomes in severe and critical COVID-19 patients. The study also underscores the importance of timing and patient selection when administering IVIG.