FGF-23 and PTH in Hemodialysis Patients
Condition: Chronic Kidney Disease Requiring Chronic Dialysis
MeSH terms: Kidney Diseases; Renal Insufficiency, Chronic
Study type: Observational [Patient Registry]

Summary: 
      In this pilot study the investigator will examine the levels of fibroblast growth factor
      (FGF-23) and parathyroid hormone (PTH) levels during hemodialysis therapy in 30 patients and
      assess the correlation between these parameters and the T-50 calcification propensity, as
      well as further parameters of secondary hyperparathyroidism (sHPT), like serum calcium (sCa),
      phosphate (P), 25-hydroxy-vitamin D (25(OH)D) and 1,25 dihydroxy-vitamin D (1,25(OH)2D).

      The investigator hypothesize that FGF-23 and PTH levels are at their highest at the beginning
      of dialysis and decrease during the treatment.
    

Detailed description: 
      Background: The development of sHPT in hemodialysis patients is a common complication which
      induces an increase in calcification and atherosclerosis. Elevated FGF-23 levels are already
      found in early stages of chronic kidney disease (CKD) and it has been shown that high FGF-23
      levels are associated with the development of cardiovascular disease and increased overall
      mortality.

      Method: In this pilot study a total number of 30 patients on maintenance haemodialysis will
      be enrolled. The investigator will examine the course of FGF-23 and PTH levels during a
      single hemodialysis session. In addition, the T-50 time, a novel non-traditional
      cardiovascular risk factor as well as further parameters of sHPT, such as serum calcium
      (sCa), phosphate (P), 25-hydroxy-vitamin D (25(OH)D) and 1,25 dihydroxy-vitamin D
      (1,25(OH)2D) will be assessed.

      Hypothesis and specific aims: The major end point of the study is the level of FGF-23 and PTH
      at three points during hemodialysis treatment. As secondary end points the T-50 calcification
      propensity and further parameters of sHPT, as well as the correlation between these
      parameters will be measured.

      Hemodialysis is classified as a kidney replacement therapy and FGF-23 and PTH are partly
      metabolized and excreted by the kidneys. Based on this the investigator hypothesize that
      FGF-23 and PTH levels are at their highest at the beginning of dialysis and decrease during
      the treatment.
    

Observational model: Cohort
Time perspective: Prospective
Sampling method: Probability Sample
Study population: 
        30 adult patients with chronic kidney disease receiving hemodialysis treatment at the
        Medical University of Vienna, Department of Internal Medicine III, Division of Nephrology
        and Dialysis. All patients are on a thrice-weekly dialysis schedule.
      
Biospecimen description: 
      Three samples per patient and dialysis treatment will be drawn at the start, after 2 hours
      and at the end of dialysis. Blood samples will be collected from the dialysis machine. Blood
      is allowed to clot, serum and plasma will be separated by centrifugation and kept in aliquots
      (500µl) at -80° until further analysis.

      Parathyroid hormone (PTH), Serum calcium (sCa), phosphate (P), 25-hydroxy-vitamin D (25(OH)D)
      and 1,25 dihydroxy-vitamin D (1,25(OH)2D) will be determined by routine assays at the
      Department of Laboratory Medicine of the General Hospital of Vienna. FGF-23 will be
      determined by an iFGF-23 enzyme-linked immunosorbent assays (ELISA) of Biomedica and the
      T50-time will be measured by an nephelometer at the Calciscon Laboratory in Switzerland.
    
Keywords: CKD; Hemodialysis; FGF 23; PTH