Risk profiles of Covid-19 patients in Spain: Study and presentation of the importance of clinical features over six waves of the pandemic

Objectives: To discover the most relevant features for predicting mortality of patients with Covid-19 and their change over the waves of the pandemic and patient stay at the hospital. Methods: A retrospective study of 83,665 patients hospitalized in different centres belonging to the Fundacion Jimenez Diaz from February 2020 to March 2022. Recorded features for each patient were evaluated for relevance in a classification task using random forests, generalized boosting models and single-variable binary classificators, repeating the process for data of each wave of the pandemic and from different moments in time during hospital stay. The resulting rankings were combined using Coppeland’s method. The results are available through a dashboard at https://covid-dashboard-cig.herokuapp.com/ Results: We find that for the common ranking, top variables coincide with the literature being: age, Oxygen saturation and common inflammation markers. Over the stay of the patient, signs of kidney failure become more relevant predictors while other inflammation markers lose relevance. Meanwhile, we find that more features stay relevant over the later waves of the pandemic, especially those relating to hepatic failure, possibly indicating patients with more comorbidities or poor responses to medication.