Correction to Lancet Gastroenterol Hepatol 2017; 2: 427–34 Petta S, Marzioni M, Russo P, et al. Ombitasvir, paritaprevir, and ritonavir, with or without dasabuvir, plus ribavirin for patients with hepatitis C virus genotype 1 or 4 infection with cirrhosis (ABACUS): a prospective observational study. Lancet Gastroenterol Hepatol 2017; 2: 427–34—In the Acknowledgments of this Article, the final sentence should read “Medical writing support was provided by Andrew Kerr of Medical Expressions and funded by Dipartimento Biomedico di Medicina Interna e Specialistica dell’Universita di Palermo.” This correction has been made to the online version as of May 5, 2017, and the printed version is correct.