Stratifying risk outcomes among adult COVID-19 inpatients with high flow oxygen: The R4 score G.M. Aguirre-García; D. Ramonfaur; G. Torre-Amione; M.T. Ramírez-Elizondo; R. Lara-Medrano; J.F. Moreno-Hoyos; E.S. Velázquez-Ávila; C.A. Diaz-Garza; V.M. Sanchez-Nava; F. Castilleja-Leal; G.M. Rhoades; M.F. Martínez-Reséndez;