Risk factors associated with the mucormycosis epidemic during the COVID-19 pandemic

This study was performed to assess the risk factors driving the epidemic of coronavirus disease 2019 (COVID-19)-associated mucormycosis (COVID–Mucor) in India that has accompanied the COVID-19 pandemic, particularly during the second wave. Risk factors were analysed among 164 participants: 132 COVID–Mucor (cases) and 32 non-COVID–Mucor (controls). Data from a prospective cohort study of mucormycosis over a period of 1 year were used. Diabetes mellitus remained a significant risk factor in both groups (97%), while uncontrolled diabetes mellitus (odds ratio (OR) 4.6; P = 0.026) and newly detected diabetes (OR 3.3; P = 0.018) were more common among the cases. Most patients with COVID–Mucor had mild COVID-19. Steroid use, often unwarranted, was highly associated with COVID–Mucor after adjusting for other risk factors (OR 28.4; P = 0.001). Serum ferritin was significantly higher (P = 0.041), while C-reactive protein was not, suggesting that alterations in iron metabolism may predispose to COVID–Mucor. Oxygen was used only in a small minority of patients with COVID–Mucor. The in-hospital mortality in both groups was low. In conclusion, the Indian COVID–Mucor epidemic has likely been driven by a convergence of interlinked risk factors: uncontrolled diabetes mellitus, unwarranted steroid use, and perhaps COVID-19 itself. Appropriate steroid use in patients with severe COVID-19 and screening and optimal control of hyperglycaemia can prevent COVID–Mucor.