Annette Bruchfeld, Francesco Pesce, Samuel Knauß, Maximilian König, Andrzej Wiecek, Carsten A. Wagner, Jolanta Malyszko, Dimitrios S. Goumenos, Francesco Trepiccione, Robert J. Unwin, Kai-Uwe Eckardt, Danilo Fliser, María José Soler, Ziad A. Massy, Ewout J. Hoorn, Kathryn Stevens, Denis Fouque, Davide Viggiano, Eugenio Gutierrez, Giovambattista Capasso, Christoph Wanner, Carmine Zoccali, Goce Spasovski, Sebastian Frische, Loreto Gesualdo, Peter J. Blankestijn, Ivan Rychlik, Dorothea Nitsch, Centre Hospitalier Lyon Sud [CHU - HCL] (CHLS), Hospices Civils de Lyon (HCL), Cardiovasculaire, métabolisme, diabétologie et nutrition (CarMeN), Institut National de la Recherche Agronomique (INRA)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Hospices Civils de Lyon (HCL), Laboratoire de Physique Nucléaire et de Hautes Énergies (LPNHE), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Veterinary Research Institute, University of Zurich, Internal Medicine, Hospices Civils de Lyon (HCL)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Université de Lyon-Institut National des Sciences Appliquées (INSA)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Institut National de la Recherche Agronomique (INRA), Viggiano, D., Wagner, C. A., Blankestijn, P. J., Bruchfeld, A., Fliser, D., Fouque, D., Frische, S., Gesualdo, L., Gutierrez, E., Goumenos, D., Hoorn, E. J., Eckardt, K. -U., Knauss, S., Konig, M., Malyszko, J., Massy, Z., Nitsch, D., Pesce, F., Rychlik, I., Soler, M. J., Spasovski, G., Stevens, K. I., Trepiccione, F., Wanner, C., Wiecek, A., Zoccali, C., Unwin, R., and Capasso, G.
Chronic kidney disease (CKD) is now seen as a systemic disease involving also the central nervous system [1], but the link between the kidney and different organ systems and disease went unnoticed for a long time. The king of Poland, Stephen Bathory (1533-86), suffered from CKD due to polycystic kidney disease and depression [2]. Similarly, Wolfgang Amadeus Mozart was also thought to have had CKD [3] and depression [4]. A list of 'Famous People Who Have Died from Kidney Disease' [5] includes many who suffered from both CKD and depression or other signs of mental illness. Is this a coincidence or actually evidence of a link between kidney disease and brain dysfunction? This is not merely an academic question because all forms of mental illness can seriously impair an individual's quality of life, and are frequently associated with progression of diseases and premature mortality, so it is worth the effort of trying to answer it. Europe and much of the industrialized countries are experiencing growing numbers of patients with CKD within their ageing populations [6]. CKD is complex and potentially fatal: (i) all organs are affected, sooner or later; (ii) the balance of plasma volume, electrolytes, acid-base and minerals, metabolites, hormones and proteins is disturbed; and (iii) patients often need a multidisciplinary team approach managing complex comorbidities, drug regimens and special diets. Although the prognosis of patients with CKD remains poor, their increasing life expectancy has shifted medical attention from life-threatening emergencies to long-term complications and sequelae, and how to improve quality of life [7]. Indeed, kidney failure has detrimental effects on health-related quality of life (HRQoL), reaching levels similar to those seen in patients with metastatic cancer [8]. This might be due to psychological factors, both kidney disease and cancer being chronic diseases with a bad prognosis. However, although the effect of CKD on quality of life is more evident in advanced stages (stage G4P) and in older patients [9, 10], a large study has shown a significant decrease in HRQoL as early as CKD stage G2 [11]. Notably, neurological and cognitive impairments [12], and depression [13] are among the most debilitating consequences of CKD contributing to the significantly reduced HRQoL [14].