1. Department of Nursing and Physiotherapy, Faculty of Nursing and Physiotherapy, Universidad de Salamanca, 37007 Salamanca, Spain
2. Instituto de Investigación Biomédica de Salamanca (IBSAL), 37007 Salamanca, Spain
3. University Hospital of Salamanca, 37007 Salamanca, Spain
4. Department of Statistics, Facultad de Medicina, Universidad de Salamanca, Campus Miguel de Unamuno, 37007 Salamanca, Spain