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Nephrol Dial Transplant. 2018 Jun 22. doi: 10.1093/ndt/gfy167. [Epub ahead of print]

The impact of symptoms on health-related quality of life in elderly pre-dialysis patients: effect and importance in the EQUAL study.

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Department of Clinical Epidemiology, Leiden University Medical Center, Leiden, The Netherlands.
Department of Clinical Sciences Intervention and Technology, Karolinska University Hospital Huddinge, Stockholm, Sweden.
UK Renal Registry, Southmead Hospital, Bristol, UK.
Clinical Epidemiology and Pathophysiology of Renal Diseases and Hypertension, Azienda Ospedaliera Bianchi Melacrino Morelli, Reggio Calabria, Italy.
Department of Nephrology and Transplantation Medicine, Wroclaw Medical University, Wroclaw, Poland.
Department of Nephrology, Skåne University Hospital, Malmö, Sweden.
ERA-EDTA Registry, Department of Medical Informatics, Academic Medical Center, University of Amsterdam, Amsterdam Public Health Research Institute, Amsterdam, The Netherlands.
Division of Nephrology, University Hospital of Würzburg, Würzburg, Germany.



Quality of life (QoL) is an important outcome in chronic kidney disease (CKD). Patients feel that symptoms are an important determinant of QoL. However, this relation is unknown. The aims of this study were to investigate the impact of the number and severity of symptoms on QoL in elderly pre-dialysis patients, assessed by both the effect of symptoms and their importance relative to kidney function, and other clinical variables on QoL.


The European Quality study (EQUAL study) is an ongoing European prospective follow-up study in late Stage 4/5 CKD patients aged ≥65 years. We used patients included between March 2012 and December 2015. Patients scored their symptoms with the Dialysis Symptom Index, and QoL with the research and development-36 (RAND-36) item Health Survey (RAND-36). The RAND-36 results in a physical component summary (PCS) and a mental component summary (MCS). We used linear regression to estimate the relation between symptoms and QoL at baseline and after 6 months, and to calculate the variance in QoL explained by symptoms.


The baseline questionnaire was filled in by 1079 (73%) patients (median age 75 years, 66% male, 98% Caucasian), and the follow up questionnaire by 627 (42%) patients. At baseline, every additional symptom changed MCS with -0.81 [95% confidence interval (CI): -0.91 to -0.71] and PCS with -0.50 (95% CI: -0.62 to -0.39). In univariable analyses, number of symptoms explained 22% of MCS variance and 11% of PCS variance, whereas estimated glomerular filtration rate only explained 1%.


In elderly CKD Stage 4/5 patients, symptoms have a substantial impact on QoL. This indicates symptoms should have a more prominent role in clinical decision-making.


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