Department of Gastroenterology, Hospital de Navarra, 31008 Pamplona, Spain;
Department of Gastroenterology, Clínica Universidad de Navarra, 31008 Pamplona, Spain;
Department of Gastroenterology, Hospital Juan Canalejo, 26131 La Coru?a, Spain;
Department of Gastroenterology, Hospital de Tarrasa, 08509 Barcelona, Spain;
Department of Gastroenterology, Hospital del Mar, 08509 Barcelona, Spain;
Department of Gastroenterology, Hospital General de Valencia, 46367 Valencia, Spain;
Department of Gastroenterology, Hospital Puerta de Hierro, 28816 Madrid, Spain;
Department of Gastroenterology, Hospital La Fe, 46367 Valencia, Spain;
Department of Gastroenterology, Hospital Gregorio Mara?ón, 28816 Madrid, Spain;
Department of Gastroenterology, Complejo Hospitalario de Toledo, 45591 Toledo, Spain;