IL-6 serum levels predict severity and response to tocilizumab in COVID-19: An observational study.

"Disclosure of potential conflict of interest: S. de la C. Rodríguez-García reports grants from Spanish Rheumatology Foundation, during the conduct of the study; nonfinancial support from Roche, Lilly, Pfizer, and Abbvie; personal fees and nonfinancial support from Novartis, Sanofi, and MSD and from UCB-Pharma, outside the submitted work. C. Fernández-Díaz reports personal fees from BMS and nonfinancial support from Novartis, outside the submitted work. J. Ancochea reports grants and personal fees from GlaxoSmithKline and Boehringer Ingelheim; grants from Linde Healthcare; and grants, personal fees, and nonfinancial support from Roche and from Chiesi, outside the submitted work. D. A. Rodríguez-Serrano reports personal fees from MSD, outside the submitted work. R. de la Camara reports personal fees from MSD, ASTELLAS, Clinigen, Janssen, Roche, and IQONE Health Care outside the submitted work. R. García-Vicuña reports grants, personal fees, and nonfinancial support from Abbvie, BMS, Lilly, Novartis, Sanofi, Sandoz, and MSD; personal fees from Biogen and Celltrion and from Mylan, outside the submitted work; personal fees and nonfinancial support from Pfizer; grants from Roche; and grants and personal fees from Janssen. C. Suarez-Fernández reports personal fees from Bayer, BMS, Daichi Sankyo, MSD, and Pfizer, outside the submitted work. C. Muñoz-Calleja reports competitive grants from Instituto de Salud Carlos III during the conduct of the study. I. González-Álvaro reports grants from Instituto de Salud Carlos III, during the course of the study; personal fees from Lilly and Sanofi; personal fees and nonfinancial support from BMS and Abbvie; research support, personal fees, and nonfinancial support from Roche Laboratories; and nonfinancial support from MSD, Pfizer, and Novartis, not related to the submitted work. The rest of the authors declare that they have no relevant conflicts of interests."

"This study was funded by Spanish Ministry of Economy, Industry and Competitiveness (MINECO) and 10.13039/501100004587Instituto de Salud Carlos III (grant nos. RD16/0011/0012 and PI18/0371 to I.G.A., grant no. PI19/00549 to A.A., and grant no. SAF2017-82886-R to F.S.-M.) and co-funded by the 10.13039/501100008530European Regional Development Fund. The study was also funded by “La Caixa Banking Foundation” (grant no. HR17-00016 to F.S.-M.) and “Fondos Supera COVID19” by Banco de Santander and CRUE. None of these sponsors have had any role in study design; in the collection, analysis, and interpretation of data; in the writing of the report; and in the decision to submit the article for publication. Disclosure of potential conflict of interest: S. de la C. Rodríguez-García reports grants from Spanish Rheumatology Foundation, during the conduct of the study; nonfinancial support from Roche, Lilly, Pfizer, and Abbvie; personal fees and nonfinancial support from Novartis, Sanofi, and MSD and from UCB-Pharma, outside the submitted work. C. Fernández-Díaz reports personal fees from BMS and nonfinancial support from Novartis, outside the submitted work. J. Ancochea reports grants and personal fees from GlaxoSmithKline and Boehringer Ingelheim; grants from Linde Healthcare; and grants, personal fees, and nonfinancial support from Roche and from Chiesi, outside the submitted work. D. A. Rodríguez-Serrano reports personal fees from MSD, outside the submitted work. R. de la Camara reports personal fees from MSD, ASTELLAS, Clinigen, Janssen, Roche, and IQONE Health Care outside the submitted work. R. García-Vicuña reports grants, personal fees, and nonfinancial support from Abbvie, BMS, Lilly, Novartis, Sanofi, Sandoz, and MSD; personal fees from Biogen and Celltrion and from Mylan, outside the submitted work; personal fees and nonfinancial support from Pfizer; grants from Roche; and grants and personal fees from Janssen. C. Suarez-Fernández reports personal fees from Bayer, BMS, Daichi Sankyo, MSD, and Pfizer, outside the submitted work. C. Muñoz-Calleja reports competitive grants from Instituto de Salud Carlos III during the conduct of the study. I. González-Álvaro reports grants from Instituto de Salud Carlos III, during the course of the study; personal fees from Lilly and Sanofi; personal fees and nonfinancial support from BMS and Abbvie; research support, personal fees, and nonfinancial support from Roche Laboratories; and nonfinancial support from MSD, Pfizer, and Novartis, not related to the submitted work. The rest of the authors declare that they have no relevant conflicts of interests."