Background Little is known about the risk factors for critical-ill events (intensive care, invasive ventilation, or death) in patients with COVID-19. Methods Patients with laboratory-confirmed COVID-19 admitted to the Wuhan Leishenshan Hospital from February 13 to March 14 was retrospectively analyzed. Demographic data, symptoms, laboratory values at baseline, comorbidities, treatments and clinical outcomes were extracted from electronic medical records and compared between patients with and without critical-ill events. The least absolute shrinkage and selection operator (LASSO) and multivariate logistic regression models were developed to explore the risk factors for critical-ill events. A risk nomogram was established to predict the probability for the critical-ill events. Survival analysis of patients with critical-ill events was performed by the Kaplan-Meier method. Results 463 COVID-19 patients were included in this study, of whom 397 were non-critically ill and 66 were critically ill (all from the intensive care unit). The LASSO regression identified four variables (hypersensitive cardiac troponin I, blood urea nitrogen , haemoglobin, and interleukin-6) contributing to the critical-ill events. Multivariable regression showed increasing odds of in-hospital critical-ill events associated with hypersensitive cTnI greater than 0.04 ng/mL (OR 20.98,95% CI 3.51-125.31), blood urea nitrogen greater than 7.6 mmol/L (OR 5.22, 95% CI 1.52-17.81, decreased haemoglobin (OR 1.06, 95% CI 1.04-1.10), and higher interleukin-6 (OR 1.05, 95% CI 1.02-1.08) on admission. Conclusions Hypersensitive cTnI greater than 0.04 ng/mL, blood urea nitrogen greater than 7.6 mmol/L, decreased haemoglobin, and high IL-6 were risk factors of critical-ill events in patients with COVID-19.