1. Department of Nephrology, Insular University Hospital of Gran Canaria, Gran Canaria, Spain;
2. Faculty of Health Sciences, University of Las Palmas de Gran Canaria, Gran Canaria, Spain;
3. Avericum Dialysis Center, Gran Canaria, Spain;
4. Department of Nephrology, University Hospital of Gran Canaria Dr Negrin, Las Palmas, Spain;
5. Faculty of Mathematics, University of Las Palmas de Gran Canaria, Gran Canaria, Spain