Acta Dermato-Venereologica 99-6CompleteContent

524 CLINICAL REPORT Strong Associations Between Inflammation, Pruritus and Mental Health in Dialysis Patients Severin SCHRICKER 1 , Thorsten HEIDER 2 , Moritz SCHANZ 1 , Jürgen DIPPON 3 , Mark Dominik ALSCHER 1 , Heinz WEISS 4 , Thomas METTANG 5 and Martin KIMMEL 1 Department of Internal Medicine, Division of General Internal Medicine and Nephrology and 4 Department of Internal Medicine, Division of Psychosomatic Medicine, Robert-Bosch-Hospital, Stuttgart, 2 Clinic for Neurology, Klinikum St. Marien Amberg, Amberg, 3 Department of Mathematics, University of Stuttgart, Stuttgart, and 5 Department of Internal Medicine, Division of Nephrology, DKD Helios Klinik, Wiesbaden, Germany 1 Pruritus, impaired mental health and inflammation contribute to morbidity in end-stage renal disease. There are no studies on all 3 conditions. We therefo- re obtained inflammatory parameter data (C-reactive protein and interleukin-6), pruritus data and psycho- logical test data (36-Item Short-Form Health Survey, “Allgemeine Depressionsskala” and Toronto Alexithy- mia Scale-20) for 19 dialysis patients with pruritus, 20 dialysis patients without pruritus and 15 healthy con- trols. Non-parametric hierarchical clustering revealed 3 clusters of parameters: one mainly driven by pruri- tus scores (chronic kidney disease-associated pruritus cluster), one by mental health scores (mental health cluster) and one by inflammatory parameters (inflam- matory cluster). Factor analysis showed strong associ- ations (mental health cluster/chronic kidney disease- associated pruritus cluster, r=–0.49; mental health cluster/inflammatory cluster, r=–0.52; inflammatory cluster/chronic kidney disease-associated pruritus cluster, r=0.48). For the first time, complete correla- tions between inflammation, mental health and pru- ritus in dialysis patients have been established. As all 3 conditions are associated with mortality, knowledge about their interdependence helps to understand end- stage renal disease pathophysiology. Key words: inflammation; IL-6; pruritus; depression; quality of life (QoL); dialysis. Accepted Jan 23, 2019; E-published Jan 23, 2019 Acta Derm Venereol 2019; 99: 524–529. Corr: PD Dr. med. Martin Kimmel, Department of Internal Medicine, Divi- sion of General Internal Medicine and Nephrology, Robert-Bosch-Hospital, Auerbachstr. 110, DE-70376 Stuttgart, Germany. E-mail: vm.kimmel@t- online.de P atients with chronic kidney disease (CKD) exhibit many alterations and comorbidities including uremic pruritus (also called CKD-associated pruritus [CKD-aP]), impaired mental health (iMH) and chronically elevated levels of inflammatory parameters (e.g. C-reactive protein [CRP] and interleukin [IL]-6). CKD-aP is asso- ciated with reduced quality of life (1) and psychosocial alterations in patients who require renal replacement therapy (RRT) (2). Based on several observations and results from various trials on CKD-aP, there is evidence that CKD-aP is a systemic disease rather than an isolated skin disease (3). The involvement of alterations of the doi: 10.2340/00015555-3128 Acta Derm Venereol 2019; 99: 524–529 SIGNIFICANCE Itch, impaired mental health and inflammation contribute to morbidity in dialysis patients. We therefore analysed la- boratory results, intensity of itch and psychological tests in dialysis patients with pruritus, without and healthy people. The data was analysed by different statistical tests. This revealed 3 independent groups. One was mainly driven by itch, one by mental health and another by inflammatory parameters. Additionally, all 3 showed strong associations. This means inflammation, mental health and itch are some how interconnected in dialysis patients. Since all 3 comor- bidities are associated with the risk of death, knowledge about the interdependence of these factors is important. immune system and a pro-inflammatory pattern (pIP) in the pathogenesis of CKD-aP has been discussed in the past, but remains still unclear (3, 4). This was noted as one of the most important fields of research in CKD (5). Additionally, the prevalence of iMH is high among patients with end-stage renal disease (ESRD) (6). It has been shown that iMH can also affect somatic outcomes (7). Of note, pIP – and especially elevation of IL-6 – was recently reported to be involved in the development of depression and other iMH conditions (8). Furthermore, pIP may be a major contributor to morbidity and mor- tality in ESRD (9). Based on this, it can be assumed that a correlation exists at least between one pair of these factors (CKD- aP, pIP and iMH). However, a simultaneous analysis and characterization of the correlations between all 3 factors is still missing. Gaining knowledge about the interde- pendence of these factors may help to understand the pathophysiological mechanisms underlying all 3 aspects of morbidity in ESRD. METHODS Patients and controls Data on hemodialysis (HD) patients (with and without CKD- aP) and controls, including inflammatory parameter data, were previously published (4). In this study, we included further data regarding 13 patients who were undergoing peritoneal dialysis (PD), and data on psychological test results, where available. This data-enriched post-hoc analysis therefore included 19 dialysis (RRT) patients with CKD-aP (“RRT-CKD-aP” subgroup: 6 PD patients and 13 HD patients) and 20 age-matched dialysis (RRT) This is an open access article under the CC BY-NC license. www.medicaljournals.se/acta Journal Compilation © 2019 Acta Dermato-Venereologica.

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