The Effects of Calcitriol on Biomarkers in Diabetic Kidney Disease Patients

Diabetic Kidney Disease (DKD) is a complication that occurs due to poor glycemic control over a long period. The decrease or loss of podocytes is an important index in determining the degree of glomerular damage. Previous studies in patients with DKD reported that vitamin D administration can improve their renal function through several mechanisms. However, there is still little evidence available regarding the effects of calcitriol on biomarkers of DKD. This trial is a double-blind randomized controlled trial to assess the effect of calcitriol in DKD patients through several biomarkers which reflect pathomechanism in DKD. Those biomarkers include urinary podocin, urinary nephrin, urinary KIM-1, urinary IL-6, plasma renin, and albuminuria.

The primary outcome is any improvement on podocyte markers, tubular markers, kidney inflammation parameters, plasma renin, and albuminuria between calcitriol and placebo groups. Secondary outcomes include the relation between each marker and the side effects of intervention therapy.

Diabetic Kidney Disease (DKD) is a complication that occurs due to poor glycemic control over a long period. The decrease or loss of podocytes is an important index in determining the degree of glomerular damage. Albuminuria and estimated glomerular filtration rate (eGFR) are currently used as the marker of DKD. However, these markers may not directly measure renal tissue injury. Thus, investigating novel biomarkers, particularly podocyte-associated biomarkers, is needed to predict DKD. Previous studies in patients with DKD reported that vitamin D administration can improve their renal function. of the various types of vitamin D, there is still little evidence available regarding the effects of calcitriol on biomarkers of DKD. Therefore, this study aimed to determine the effect of calcitriol on podocyte damage markers, tubular injury markers, kidney inflammation parameter, plasma renin, dan albuminuria in DKD patients.

This study is a double-blind randomized controlled clinical trial to assess the effect of calcitriol in DKD patients through several markers including albuminuria. Podocyte damage is characterized by urinary podocin and urinary nephrin, tubular marker injury is characterized by urinary KIM-1, kidney inflammation is represented by urinary IL-6, hemodynamic is represented by plasma renin.

The primary outcome is any improvement on those markers between calcitriol and placebo groups. And the secondary outcomes include the relation between each marker and the side effects of intervention therapy.

Eligibility Criteria:
Inclusion Criteria:

* Controlled type 2 diabetes mellitus with HbA1C at least \<8% and albuminuria (UACR\>30 mg/mmol)
* Estimated Glomerular Filtration Rate (eGFR) \>45 ml/min/1.73 m2
* Agree to participate in the research

Exclusion Criteria:

* Uncontrolled hypertension with routine Angiotensin-converting-enzyme inhibitors (ACEi) or Angiotensin II receptor blockers (ARBs) treatment
* Hypercalcemia (total serum Ca level \>10/5 mg/dL)
* Hyperphosphatemia (total serum phosphate level \>5 mg/dL)
* Hypersensitivity to calcitriol
* Suffering from other diseases that cause proteinuria
* Acute diseases
* Smoker or previous smoking history
* Taking medications or suplements that can affect calcitriol metabolism (thiazide, digoxin, anti-convulsant)