BACKGROUND: COVID-19 disease has been a deadly pandemic in different waves in the Democratic Republic of Congo. However, knowledge of the clinical characteristics of COVID-19 patients and the factors associated with death during different waves is important. METHODS: We conducted a retrospective cohort of 410 patients hospitalized during 4 waves of COVID-19, from March 20, 2020, to January 2, 2022, at the Ngaliema clinic in DR Congo. We included any patient hospitalized for COVID-19 with biological confirmation by RT-PCR. Factors associated with death were investigated using logistic regression. RESULTS: During the 4 waves of the COVID-19 pandemic at Clinique Ngaliema, complaints on admission were most often fever, cough and physical asthenia. Death was most common in the elderly, hypertensive and diabetic patients, those with elevated CRP and hyper leukocytosis. Mortality was highest in the 1st wave (28%), followed by the 3rd wave (27%), then the 2nd (22%) and 4th waves (21%). Factors associated with death were hyper leukocytosis (ORa: 2.76
CI 95%: 1.25-6.1), severe disease stage (ORa 21.24
CI 95%: 1.87-24). Vitamin C 500 mg twice a day use was protective (ORa: 0.24
CI 95%: 0.08-0.72). CONCLUSION: COVID-19 disease poses a real public health problem, with non-negligible mortality. Factors associated with death were degree of disease severity, hyper leukocytosis and non-use of vitamin C. Taking these factors into account will help clinicians and decision-makers to anticipate future waves of the pandemic.