A Study of The Effect of Altitude on Mircera (Methoxy Polyethylene Glycol-Epoetin Beta) Dose Requirements in Participants With Chronic Renal Anemia in Pre-Dialysis or Dialysis

Inclusion Criteria: * Adult participants, \>/= 18 years of age * Chronic kidney disease stage III-IV or V * Probable start of dialysis within 18 months (pre-dialysis group) * Hemodialysis or peritoneal dialysis in a stable regimen for at least 3 months (dialysis group) * Adequate iron status * Females of childbearing potential must agree to use two effective methods of contraception during the study and for at least 2 months following the last dose of study drug Exclusion Criteria: * Failing renal allograft in place * Acute or chronic bleeding within 8 weeks prior to screening * Transfusion of red blood cells within 8 weeks prior to screening * Poorly controlled hypertension, defined as hypertension that needs hospitalization to obtain control * History of seizures, hemoglobinopathies and/or severe liver disease * Active malignant disease, except for non-melanoma skin cancer * Immunosuppressive therapy in the 12 weeks prior to screening * Treatment with any other investigational agent or participation in a clinical trial within 28 days prior to enrolment * Known hypersensitivity to Mircera (methoxy polyethylene glycol-epoetin beta) or any of its excipients * Pregnant or lactating women