A Study of Methoxy Polyethylene Glycol-epoetin Beta (Mircera) in Participants With Chronic Kidney Disease (PRIMAVERA)

The yearly reduction in eGFR was calculated using the MDRD-4 formula. This formula is based on age, sex, and serum creatinine and eGFR values are calculated as follows: GFR in milliliter per minute (mL/min) per 1.73 meter square (m^2) = 175 x Serum Cr^-1.154 x age^-0.203 x 0.742 (if female). The yearly reduction rate (mL/min/1.73m^2 / Year) is defined as -365.25 multiplied by Beta, where Beta is the slope parameter derived for each participants separately by simple linear regression of the change from baseline in participant's eGFR measurements (from Baseline to Visit 24) on the actual day of measurement.

The eGFR value calculated using the CKD-EPI equation. The formula used is based on age, sex, ethnicity, and serum creatinine and eGFR values are calculated as follows: GFR in mL/min per 1.73 m^2 = 141 x min (SerumCr/k; 1)^a x max(SerumCr/k; 1)^(-1.209) x 0.993^age x F x B, where k=0.7 for female (else=0.9); a=-0.329 for female (else=-0.411), F=1.018 for female (else=1), B=1.159 for black (else=1), min/max=minimum/maximum of listed values. The Yearly Reduction Rate (mL/min/1.73m^2 / Year) is defined as -365.25 x Beta, where Beta is the slope parameter derived for each participant separately by simple linear regression of the change from baseline in participant's eGFR measurements (from Baseline to Visit 24) on the actual day of measurement.

Creatinine clearance was calculated according to the Cockcroft and Gault Formula. It measures rate creatinine (substance formed from metabolism of creatine) is cleared from blood by kidneys. Normal adult creatinine clearance is greater than or equal to (>=) 90 mL/min. Change from baseline=CC at Week X minus CC at baseline where higher scores represented improved renal function.

Serum creatinine is an indicator of kidney function. Creatinine is a substance formed from the metabolism of creatine, commonly found in blood, urine, and muscle tissue. It is removed from the blood by the kidneys and excreted in urine. Normal adult blood levels of creatinine=45 to 90 micromoles per liter (mcmol/L) for females, 60 to 110 mcmol/L for males, however normal values are age-dependent.

UACR is defined as the ratio: milligram of albumin per gram of creatinine. The presence of albumin in the urine (macroalbuminuria) is a marker of kidney disease. Albumin and creatinine concentrations were obtained from spot urine samples.

Cystatin C is a protein which is mainly used as a biomarker of kidney function. If kidney function and GFR decline, the blood levels of cystatin C rise.

An AE was any untoward medical occurrence in a participant who received study drug without regard to possibility of causal relationship. An SAE was an AE resulting in any of the following outcomes or deemed significant for any other reason: death; initial or prolonged inpatient hospitalization; life-threatening experience (immediate risk of dying); persistent or significant disability or incapacity; and congenital anomaly. Percentage of participants with AEs included participants affected with both SAEs and non-SAEs.