Study to Evaluate Safety of Vitamin D Receptor Activators in Patients Ages 0 to 16 With Chronic Kidney Disease Stage 5 Receiving Peritoneal Dialysis Within Current Clinical Practice

1. Male or female between 0 to 16 years of age (inclusive), on peritoneal dialysis for at least 30 days. 2. The patient has a history of secondary hyperparathyroidism as defined by having initiated a vitamin D receptor activator to treat an elevated parathyroid hormone level. 3. The patient is attending a site associated with North America Pediatric Renal Trials and Collaborative Studies (NAPRTCS) Dialysis Registry. 4. Patient and the patient's parent or legal guardian must voluntarily sign and date an informed consent and/or assent, approved by the local Independent Ethics Committee/Institutional Review Board, prior to the initiation of any screening or study-specific procedures. 5. Patient has received paricalcitol or calcitriol for a minimum of 10 days.

1. Patient is scheduled for a kidney transplant within 3 months. 2. Patient is expected to stop peritoneal dialysis within 3 months. 3. Patient is expected to transfer to hemodialysis within 3 months. 4. Patient is planning to be enrolled in an investigational study where the drug and/or dose are unknown to the investigator within the first 3 months from the date of patient enrollment.