S.A. declares no competing interests. I.L. has received grants paid to The University of Texas Southwestern Medical Center from Novo Nordisk, Pfizer, Merck, Sanofi, Boehringer Ingelheim and Mylan, and has received consulting fees and travel expenses from Novo Nordisk, Eli Lilly, Johnson & Johnson, Merck, Pfizer, Sanofi, Boehringer Ingelheim, Zealand, Bayer, Intercept, Valeritas, Structure, Carmot, Shionoghi, Mediflix and WebMD.