Supplementary Material for: Quality of Life in Dialysis Patients: A Retrospective Cohort Study

<b><i>Background/Aim:</i></b> Physical component summary (PCS) and mental component summary (MCS) scores are associated with hospitalization and mortality in patients with end-stage renal disease. Most studies in these patients are cross-sectional in nature. This study aimed to assess the dynamics of health-related quality of life (HRQOL) over time, as well as determinants of changes in HRQOL. Also, the relation between changes in HRQOL with respect to both hospitalization and mortality was assessed. <b><i>Methods:</i></b> A cross-sectional analysis was performed in 77,848 hemodialysis (HD) patients whereas changes in HRQOL were assessed in 8,339 patients over a 1-year time period. HRQOL measurements were assessed with Kidney Disease Quality of Life-36 questionnaires. Also, relevant biomarkers (albumin, creatinine, hemoglobin, sodium) and equilibrated normalized protein catabolic rate (enPCR) were measured. <b><i>Results:</i></b> HRQOL were found to be decreased in HD patients. Nutritional indices like creatinine (r = 0.23; p < 0.0001) and serum albumin (r = 0.21; p < 0.0001) positively correlated with PCS scores. An increase in levels of albumin, creatinine, hemoglobin, enPCR and serum sodium over time are significantly (p < 0.0001) associated with positive changes in PCS scores. Changes in PCS scores were found to be predictive for hospitalization and mortality. The correlates of predictors for MCS scores were less strong compared to that of PCS scores. The strongest positive predictors of MCS scores were age (r = 0.08; p < 0.0001), albumin (r = 0.05; p < 0.0001) and sodium (r = 0.05; p < 0.0001). <b><i>Conclusions:</i></b> Nutritional factors are strongly associated with changes in HRQOL, especially with regard to PCS scores (change over time in HRQOL was an independent predictor of hospitalization and mortality). Increased scores of HRQOL over time are positively associated with survival.