Chronic related group classification system as a new public health tool to predict risk and outcome of COVID-19 in patients with systemic rheumatic diseases: A population-based study of more than forty thousand patients

Enrico De Lorenzis, Paolo Parente, Gerlando Natalello, Salvatore Soldati, Silvia Laura Bosello, Andrea Barbara, Chiara Sorge, Svetlana Axelrod, Lucrezia Verardi, Pier Giacomo Cerasuolo, Giusy Peluso, Antonella Gemma, Marina Davoli, Donatella Biliotti, Vincenzo Bruzzese, Mauro Goletti, Mirko Di Martino, Maria Antonietta D'Agostino^*