1. Federal University of Rio Grande do norte; Department of Medicine; Alameda jauaperi 1083 São Paulo Vila Clementino Brazil 04523-014
2. Federal University of São Paulo; Sao Paulo Brazil
3. Universidade Federal de São Paulo / Escola Paulista de Medicina; Brazilian Cochrane Centre; Rua Pedro de Toledo 598 Vila Clementino São Paulo SP Brazil CEP 04039-001
4. Federal University of São Paulo; Gastroenterology; R. Botucatu 740 20 ANDAR São Paulo Brazil 04023-900