1. Graduate Program, School of Nursing, Federal University of Rio Grande do Sul, Rua São Manoel 963, Bairro Rio Branco, 90620-110 Porto Alegre, RS, Brazil
2. Cardiology Division, Heart Failure Clinic, Hospital de Clinicas de Porto Alegre, Porto Alegre, RS, Brazil
3. University of Pennsylvania School of Nursing, Philadelphia, PA, USA
4. Statistics Department, Mathematics Institute, Federal University of Rio Grande do Sul, Porto Alegre, RS, Brazil
5. Graduate Program in Epidemiology, Federal University of Rio Grande do Sul School of Medicine, Porto Alegre, RS, Brazil