Clinical Drug Investigation published the results of a study by Heidenreich et al. [1] in which the authors described efficacy and safety outcomes in a cohort of patients with chronic kidney disease (CKD) not on dialysis receiving C.E.R.A., a continuous erythropoietin receptor activator (Mircera , Roche Registration Limited, Welwyn Garden City, UK), at monthly intervals. Reduced frequency of erythropoiesis stimulating agent (ESA) dosing is a wellestablished clinical objective in nephrology, with the potential to improve patient satisfaction and compliance, as well as reducing outpatient staffing or hospital time. Encouragingly, the efficacy and safety of once-monthly dosing with C.E.R.A. versus shorter-acting ESA therapies has been convincingly demonstrated in randomized trials in dialysis-dependent [2–4] and non-dialysis [1, 3, 5, 6] patients with CKD. Subsequently, multicenter observational studies have confirmed that hemoglobin control is maintained after conversion of dialysis [7, 8] and nondialysis [1] CKD patients to C.E.R.A. under routine clinical conditions, and is well-tolerated. Heidenreich et al. [1] described the results of a patient satisfaction survey, which indicated that more than half of the patients who had previously received another ESA were more satisfied with C.E.R.A. Their analysis, however, did not specify the method of administration of prior ESA agents, which may have influenced patient attitudes. Epoetin beta and darbepoetin are available as multi-dose pen application systems (epoetin beta is also offered in multi-dose vials), which are convenient for patients and staff and reduce pain at the injection site [9]. These systems also permit small adjustments in dose (250 IE) that can be performed every time these shorter-acting ESAs are administered. C.E.R.A. is provided only as pre-filled syringes with a minimum incremental dose difference of 20 lg. We undertook a non-interventional, observational study at 15 nephrology centers in Germany, in which dialysisdependent CKD patients previously receiving ESA administered by multi-dose application systems using special vials or pens were followed up for 9 months after their physician had decided to switch to once-monthly C.E.R.A. therapy using pre-filled syringes. C.E.R.A. was initiated and prescribed at the investigator’s discretion. Patients were required to have serum ferritin [200 ng/mL and anemia caused only by CKD, and with no acute blood loss or hemoglobin decrease within the preceding 4 weeks. The key endpoints were hemoglobin stability and patient satisfaction regarding ESA therapy (‘satisfied’, ‘undecided’, and ‘not satisfied’). In total, 238 patients were enrolled and received at least one dose of C.E.R.A. Of these, 201 (84.5 %) completed the 9-month study on-treatment. Overall, 221 patients (92.9 %) met the criteria for inclusion in the patient satisfaction analysis and 142 patients (59.7 %) were eligible for the efficacy analysis (missing data was the main reason for exclusion from the efficacy analysis). Prior to study entry, 87 patients (36.6 %) were receiving epoetin beta using a pen system (NeoRecormon , Roche Registration Limited, Welwyn Garden City, UK), 34 patients (14.3 %) were receiving epoetin beta using multidose vials (NeoRecormon Multidose 50,000, Roche Registration Limited, Welwyn Garden City, UK), 52 F. Bozkurt (&) Nephrologisches Zentrum, Daun, Germany e-mail: 065927275@t-online.de