Vitamin D and Coronary Calcification Study
Condition: Chronic Kidney Disease; Vitamin D Deficiency; Coronary Calcification; Disorders of Calcium and Bone Metabolism
MeSH terms: Kidney Diseases; Renal Insufficiency, Chronic; Vitamin D Deficiency; Calcinosis
Intervention: Calcitriol (Rocaltrol®); Paricalcitol
Intervention description: Subjects taking calcitriol will be started at 0.25 mcg 3x/week and titrated up during the next visit according to PTH levels. If at the 12 week visit, PTH is still not at goal, then calcitriol will be increased to 0.5 mcg 3x/week.; Subjects taking paricalcitol will be started at 2 mcg 3x/week and titrated up during the next visit according to PTH levels. If at the 12 week visit, PTH is still not at goal, then paricalcitol will be increased to 4 mcg 3x/week.
Intervention MeSH terms: Calcitriol
Phase: Phase 4
Study type: Interventional
Primary purpose: Prevention
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor)
Enrollment: 44.0
Sex: All
Minimum age: 25 Years
Healthy volunteers: No
Keywords: Secondary Hyperparathryoidism; Chronic Kidney Disease; Vitamin D; Coronary Calcification; Bone metabolism

Summary:

      Patients with chronic kidney disease (CKD) have a higher mortality rate than the general
      population, with cardiovascular disease (CVD) accounting for approximately 50% of deaths.
      Vascular calcification is a common finding in patients with CKD. Furthermore, patients with
      CKD develop secondary hyperparathyroidism, partly because of a decrease of calcitriol
      synthesis on the kidney. Treatment of secondary hyperparathyroidism includes use of activated
      vitamin D including calcitriol and paricalcitol. Recent evidence in dialysis patients suggest
      an improved survival in patients using paricalcitol compared to calcitriol.

      Studies in uremic rats suggests that there are differential effects of calcitriol and
      paricalcitol in expression of markers of soft-tissue calcification independent of
      calcium-phosphorus product. Calcitriol increased calcification of vascular smooth muscle
      cells cultured in calcification media. There was also significant increase in pulse pressure
      in animals treated with calcitriol.

      The investigators hypothesize that these different forms of vitamin D may have differential
      effects in vascular calcification progression in CKD patients.
    

Eligibility criteria:

        Inclusion Criteria:

          -  CKD stages 3 or 4 (estimated glomerular filtration rate (eGFR) between 15 and 59)

          -  Diagnosis of secondary hyperparathyroidism, which is defined as:

               -  Elevated intact PTH (iPTH) as per KDIGO guidelines:

                    -  CKD stage 3 (eGFR 30-59) or CKD stage 4 (eGFR 15-29) with iPTH > Upper Limit
                       of Normal for lab (6.8 pmol/L)

          -  Presence of Coronary Artery Calcium (CAC > 0)

          -  Subject will be able to complete the study, to the best of his/her knowledge

        Exclusion Criteria:

          -  iPTH >1500 pg/ml

          -  Current or previous use of bisphosphonates

          -  History of parathyroidectomy or anticipated parathyroidectomy

          -  History of cinacalcet use

          -  History of a solid organ transplant or scheduled date for transplant surgery

          -  History of coronary revascularization (coronary artery bypass surgery or percutaneous
             intervention)

          -  History of coronary artifact (e.g. pacemaker, intracardiac defibrillator, artificial
             valve or biventricular leads)

          -  Active atrial fibrillation

          -  Weight greater than 300 pounds (due to limitations of equipment)

          -  HIV positive

          -  Current pregnancy (although pregnancy is very rare in the CKD population)

          -  Life expectancy less than two years as judged by primary physician

          -  Institutionalized patients (nursing home or prisoners)

          -  Language barrier or mental incapacity to consent

          -  Inability to swallow tablets or current gastrointestinal disorder that may be
             associated with impaired absorption of orally administered medications.