1. Department of Nephrology, Central Defense Gomez Ulla Hospital, Madrid, Spain
2. Department of Nephrology, Doctor Negrín University Hospital, Las Palmas de Gran Canaria, Spain
3. Department of Cardiology, Central Defense Gomez Ulla Hospital, Madrid, Spain
4. Department of Hemodialysis, Avericum S.L., Las Palmas de Gran Canaria, Spain