Comparative Assessment of Mortality Risk Factors Between Admission and Follow-up Models Among Patients Hospitalized with COVID-19

Neto, Felippe Lazar; Salzstein, Guilherme A.; Cortez, André L.; Bastos, Thaís L.; Baptista, Fabíola V.D.; Alves, Joanne; Lauterbach, Gerhard P.; de Oliveira, Julio Cesar; de Assis, Fábio C.; Aguiar, Marília R.A.; de Deus, Aline A.; Dias, Marcos Felipe D.S.; Sousa, Felipe C.B.; Duailibi, Daniel F.; Kondo, Rodrigo H.; de Moraes, Augusto C.F.; Martins, Milton A.

OBJECTIVES: We aim to compare differences in mortality risk factors between admission and follow-up incorporated models. METHODS: A retrospective cohort study with 524 patients with confirmed COVID-19 infection admitted to a tertiary medical center in São Paulo, Brazil, from March 13(th) to April 30(th), 2020. We collected data at admission, 3(rd), 8(th) and 14(th) day of hospitalization. We calculated the hazard ratio (HR) and compared 28-day in-hospital mortality risk factors between admission and follow-up models using a time-dependent Cox regression model. RESULTS: Of 524 patients, 50.4% needed mechanical ventilation. The 28-day mortality rate was 32.8%. Compared to follow-up, admission models under-estimated the mortality HR for peripheral oxygen saturation<92% (1.21 versus 2.09), heart rate>100bpm (1.19 versus 2.04), respiratory rate>24ipm (1.01 versus 1.82) and mechanical ventilation (1.92 versus 12.93). Low oxygen saturation, higher oxygen support and more biomarkers including lactate dehydrogenase, c-reactive protein, neutrophil-lymphocyte ratio and urea remained associated with mortality after adjustment for clinical factors at follow-up compared to only urea and oxygen support at admission. CONCLUSIONS: The inclusion of follow-up measurements changed mortality hazards of clinical signs and biomarkers. Low oxygen saturation, higher oxygen support, lactate dehydrogenase, c-reactive protein, neutrophil-lymphocyte ratio and urea could help prognose patients during follow-up.