Effect of interferon-α on COVID-19 in-hospital mortality: a large-scale propensity score-matched study.

Background:  Coronavirus infection can induce the production of inflammatory cytokines leading to acute respiratory distress syndrome (ARDS) and death. It is well-established that interferons (IFNs) are essential in regulating the immune response, thus their effects of IFNs on COVID-19 patients should be subject to investigation. This study aimed to investigate the effects of IFN-α alone or in combination with remdesivir in hospitalized COVID-19 patients.

Material and methods:  A multicentre, retrospective study was conducted on COVID-19 patients admitted to three hospitals in Tehran, Iran, from March 20, 2020, to March 18, 2021. The unadjusted and adjusted effects of IFN-α on COVID-19 outcomes were investigated through propensity score matching (PSM) to achieve a 1:1 balanced dataset.

Results: Among 4,782 patients, 3,764 were eligible for the study, including 1,704 patients (45.27%) receiving at least one treatment with IFN-α and 2,060 controls not receiving IFN-α. After PSM, 851 IFN-α patients and 851 controls were recruited in the PSM analysis with a median age of 60.8 (standard deviation [SD]: 16.2 and 60.9 [SD: 17.4]), respectively. The PSM results showed no significant difference between the survival curves of the IFN-α group and the control group (p=0.340). However, the unadjusted impact of IFN-α on the risk of mortality was statistically significant (p=0.043, hazard-ratio: 0.86; 95% confidence interval [CI]: 0.75-0.99). Also, the combination of IFN-α and remdesivir had no significant benefit (HR: 89, 95% CI: 0.74-1.34).

Conclusion: Our findings indicate that subcutaneous administration of IFN-α, with or without remdesivir, does not have any significant impact on COVID-19 mortality and ICU admission. Future clinical trials considering the time, subtype, and form of IFN-α administration are warranted to investigate the potential therapeutic effects of IFN-α on COVID-19.