Please select the eligibility criteria that correspond to the clinical trial below.
Title: Fibroblast Growth Factor-23 Reduction in Predialysis Chronic Kidney Disease
Brief Summary: The investigators would like to study the role of phosphorus metabolism in the development of certain hormonal problems in people with chronic kidney disease (CKD). More specifically, the goals of the research are (1) to understand the cause of hyperparathyroidism - a hormone problem that often develops in patients who have kidney disease and (2) to test whether decreasing phosphorus intake could help improve or prevent hyperparathyroidism.


Options:
A: Inclusion Criteria:

* Age \> 18 years
* Capable of giving informed consent
* Duration of peritoneal dialysis \> 3 months
* Dose of phosphate binder(s) stable over previous 2 week period
* Plasma phosphours \> 4.9 mg/dL based on most recent laboratory data within 1 month of enrollment

Exclusion Criteria:

* Pregnancy
* Known liver disease
* Active peptic ulcer disease
* Treatment with carbamazepine
* Intolerance to niacinamide or niacin
* Current medication regimen including niacin or niacinamide \> 100 mg daily
* Planned or expected surgical procedure in the next 4 months
* Patients in nursing home or extended care facilities where administration of the study drug may not be appropriately given
B: Inclusion Criteria:

* Men or women greater than 18 years of age.
* The subject has voluntarily signed and dated the most recent informed consent form approved by an Institutional Review Board (IRB).

Exclusion Criteria:

* Receiving hemodialysis.
* Receiving or has received an investigational product (or is currently using an investigational device) within 28 days prior to Visit 2.
* Evidence of active and clinically significant infection at Visit 2.
* Dental work within 48 hours prior to Visit 2.
C: Inclusion Criteria:

* Most recent phosphorus and mean phosphorus over last 3 months \> 5.5 mg/dL
* Age ≥ 18 years
* On chronic hemodialysis ≥ 6 months
* English speaking

Exclusion Criteria:

* Mentally incompetent
* AIDS
* Cancer
* Terminal illness
* Pregnancy
* Nursing home residence
* No telephone access
* In another phosphorus related study
* Unable to identify written words
D: Inclusion Criteria:

* We will include stage 3a, 3b and 4 CKD patients, aged 18 years or over with normal serum phosphate levels (≤ 4.6 mg/dl)

Exclusion Criteria:

* Patients with rapidly advancing renal failure who thus might develop hyperphosphatemia or end stage renal disease requiring initiation of dialysis during the study period
* Patients expected to require dialysis initiation within the follow up period
* Patients with hyperphosphatemia \> 4.6 mg/dl
* Patients with any previous or current treatment with phosphate binders or active vitamin D (doxercalciferol or calcitriol)
* Malnutrition, defined as a serum albumin \< 3.0 mg/dl
* Patients with liver disease (ALT or AST \> 100 U/L) or cholestasis (direct bilirubin \> 1.0 mg/dl) because this can limit their ability to absorb fat soluble vitamins such as vitamin D
* Anemia, defined as a hematocrit \< 27% at the screening visit
* Medical conditions impacting Pi metabolism-primary hyper- or hypoparathyroidism; Patients with previous subtotal parathyroidectomy; gastrointestinal malabsorption disorders such as Crohn's Disease, ulcerative colitis, celiac disease, or severe liver dysfunction;
* Patients with outpatient counseling by a renal nutritionist within the previous 6 months
* Hospitalization within the previous 4 weeks
* Pregnancy or breastfeeding mothers
* Patients unable to independently provide written informed consent - prisoners, mentally incompetent, minors

Answer: D