OBJECTIVE To describe the clinical characteristics and outcomes of adult patients with severe COVID-19, with the exploration of risk factors for mortality in the hospital. METHODS This study included 20 adult patients diagnosed with COVID-19 admitted to the ICU of DHQ Hospital, Faisalabad (Pakistan). Patients were categorised into the survival group and the death group according to the outcome. We retrieved demographics, clinical manifestations and signs, laboratory indicators, treatment measures and clinical outcomes from the medical record, and summarised the clinical characteristics and outcomes of these patients. RESULTS The average age of patients was 70 ± 12 years, of which 40% were male. They were admitted to the ICU 11 days after the onset of symptoms. The most common symptoms on admission were cough (19 cases, 95%), fatigue or myalgia (18 cases, 90%), fever (17 cases, 85%) and dyspnoea (16 cases, 80%). Eleven (55%) patients had underlying diseases, of which hypertension was the most common (11 cases, 55%), followed by cardiovascular disease (4 cases, 20%) and diabetes (3 cases, 15%). Six patients (30%) received invasive mechanical ventilation and continuous renal replacement therapy and eventually died. Acute heart injury was the most common complication (19 cases, 95%). Ten (50%) patients died between 2 and 19 days after admission to the ICU. Compared with dead patients, the average body weight of surviving patients was lower (61.70 ± 2.36 vs 68.60 ± 7.15, P = .01), Glasgow Coma Scale score was higher (14.69 ± 0.70 vs 12.70 ± 2.45, P = .03), with fewer concurrent shocks (2 vs 10, P = .001) and acute respiratory distress syndrome (2 vs 10, P = .001). CONCLUSIONS The mortality rate is high in critically ill patients with COVID-19. Lower Glasgow Coma Scale, higher body weight and decreased lymphocyte count appear to be potential risk factors for the death of patients with COVID-19 in the ICU.