@article{SchneiderGutjahrLengsfeldRitzetal.2014,
  author    = {Schneider, Andreas and Gutjahr-Lengsfeld, Lena and Ritz, Eberhard and Scharnagl, Hubert and Gelbrich, G{\"o}tz and Pilz, Stefan and Macdougall, Iain C. and Wanner, Christoph and Drechsler, Christiane},
  title     = {Longitudinal Assessments of Erythropoietin-Stimulating Agent Responsiveness and the Association with Specific Clinical Outcomes in Dialysis Patients},
  series = {Nephron Clinical Practice},
  volume    = {128},
  journal   = {Nephron Clinical Practice},
  number    = {1-2},
  issn      = {1660-2110},
  doi       = {10.1159/000367975},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-196511},
  pages     = {147-152},
  year      = {2014},
  abstract  = {Background: Dose requirements of erythropoietin-stimulating agents (ESAs) can vary considerably over time and may be associated with cardiovascular outcomes. We aimed to longitudinally assess ESA responsiveness over time and to investigate its association with specific clinical end points in a time-dependent approach. Methods: The German Diabetes and Dialysis study (4D study) included 1,255 diabetic dialysis patients, of whom 1,161 were receiving ESA treatment. In those patients, the erythropoietin resistance index (ERI) was assessed every 6 months during a median follow-up of 4 years. The association between the ERI and cardiovascular end points was analyzed by time-dependent Cox regression analyses with repeated ERI measures. Results: Patients had a mean age of 66 ± 8.2 years; 53\% were male. During follow-up, a total of 495 patients died, of whom 136 died of sudden death and 102 of infectious death. The adjusted and time-dependent risk for sudden death was increased by 19\% per 5-unit increase in the ERI (hazard ratio, HR = 1.19, 95\% confidence interval, CI = 1.07-1.33). Similarly, mortality increased by 25\% (HR = 1.25, 95\% CI = 1.18-1.32) and infectious death increased by 27\% (HR = 1.27, 95\% CI = 1.13-1.42). Further analysis revealed that lower 25-hydroxyvitamin D levels were associated with lower ESA responsiveness (p = 0.046). Conclusions: In diabetic dialysis patients, we observed that time-varying erythropoietin resistance is associated with sudden death, infectious complications and all-cause mortality. Low 25-hydroxyvitamin D levels may contribute to a lower ESA responsiveness.},
  language  = {en}
}
@article{SchneiderSchneiderScharnagletal.2013,
  author    = {Schneider, Andreas and Schneider, Markus P. and Scharnagl, Hubert and Jardine, Alan G. and Wanner, Christoph and Drechsler, Christiane},
  title     = {Predicting erythropoietin resistance in hemodialysis patients with type 2 diabetes},
  series = {BMC Nephrology},
  volume    = {14},
  journal   = {BMC Nephrology},
  number    = {67},
  doi       = {10.1186/1471-2369-14-67},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-128695},
  year      = {2013},
  abstract  = {Background: Resistance to ESAs (erythropoietin stimulating agents) is highly prevalent in hemodialysis patients with diabetes and associated with an increased mortality. The aim of this study was to identify predictors for ESA resistance and to develop a prediction model for the risk stratification in these patients. Methods: A post-hoc analysis was conducted of the 4D study, including 1015 patients with type 2 diabetes undergoing hemodialysis. Determinants of ESA resistance were identified by univariate logistic regression analyses. Subsequently, multivariate models were performed with stepwise inclusion of significant predictors from clinical parameters, routine laboratory and specific biomarkers. Results: In the model restricted to clinical parameters, male sex, shorter dialysis vintage, lower BMI, history of CHF, use of ACE-inhibitors and a higher heart rate were identified as independent predictors of ESA resistance. In regard to routine laboratory markers, lower albumin, lower iron saturation, higher creatinine and higher potassium levels were independently associated with ESA resistance. With respect to specific biomarkers, higher ADMA and CRP levels as well as lower Osteocalcin levels were predictors of ESA resistance. Conclusions: Easily obtainable clinical parameters and routine laboratory parameters can predict ESA resistance in diabetic hemodialysis patients with good discrimination. Specific biomarkers did not meaningfully further improve the risk prediction of ESA resistance. Routinely assessed data can be used in clinical practice to stratify patients according to the risk of ESA resistance, which may help to assign appropriate treatment strategies.},
  language  = {en}
}
@article{SchneiderSchneiderKrieteretal.2015,
  author    = {Schneider, Andreas and Schneider, Markus P. and Krieter, Detlef H. and Genser, Bernd and Scharnagl, Hubert and Stojakovic, Tatjana and Wanner, Christoph and Drechsler, Christiane},
  title     = {Effect of high-flux dialysis on circulating FGF-23 levels in end-stage renal disease patients: results from a randomized trial},
  series = {PLoS ONE},
  volume    = {10},
  journal   = {PLoS ONE},
  number    = {5},
  doi       = {10.1371/journal.pone.0128079},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-148559},
  pages     = {e0128079},
  year      = {2015},
  abstract  = {Background In patients undergoing maintenance hemodialysis (HD), increased levels of circulating fibroblast growth factor-23 (FGF-23) are independently associated with cardiovascular events and mortality. Interventional strategies aiming to reduce levels of FGF-23 in HD patients are of particular interest. The purpose of the current study was to compare the impact of high-flux versus low-flux HD on circulating FGF-23 levels. Methods We conducted a post-hoc analysis of the MINOXIS study, including 127 dialysis patients randomized to low-flux (n = 62) and high-flux (n = 65) HD for 52 weeks. Patients with valid measures for FGF-23 investigated baseline and after 52 weeks were included. Results Compared to baseline, a significant increase in FGF-23 levels after one year of low-flux HD was observed (Delta plasma FGF-23: +4026 RU/ml; p < 0.001). In contrast, FGF-23 levels remained stable in the high flux group (Delta plasma FGF-23: +373 RU/ml, p = 0.70). The adjusted difference of the absolute change in FGF-23 levels between the two treatment groups was statistically significant (p < 0.01). Conclusions Over a period of 12 months, high-flux HD was associated with stable FGF-23 levels, whereas the low-flux HD group showed an increase of FGF-23. However, the implications of the different FGF 23 time-trends in patients on high flux dialysis, as compared to the control group, remain to be explored in specifically designed clinical trials.},
  language  = {en}
}