Does a history of kidney stones alter vitamin D (Vitamin D) supplementation recommendations?

Vitamin D Recommendations for Patients with Kidney Stones

For patients with a history of kidney stones, vitamin D supplementation should be prescribed cautiously with monitoring of urinary calcium, as these patients may be at increased risk for hypercalciuria when supplemented, though vitamin D deficiency should still be corrected. 1

Assessment and Monitoring Approach

• Assess 25-hydroxyvitamin D [25(OH)D] levels in patients with kidney stones, as vitamin D insufficiency is common in this population (affecting approximately 80-90% of patients with CKD) 1
• Monitor serum calcium, urinary calcium excretion, and parathyroid hormone (PTH) levels before and during vitamin D supplementation in stone formers 2, 3
• Stone formers with hypercalciuria tend to have higher 25(OH)D values compared to those with normal urinary calcium, suggesting a potential relationship between vitamin D status and stone risk 4

Supplementation Guidelines

• For vitamin D deficiency/insufficiency in patients with kidney stones:

  • Use cholecalciferol (vitamin D3) or ergocalciferol (vitamin D2) to correct deficiency, with cholecalciferol potentially having higher bioefficacy 1
  • Start with lower doses and titrate based on 25(OH)D levels and urinary calcium response 1, 5
  • Target 25(OH)D levels of at least 30 ng/mL (75 nmol/L) to prevent secondary hyperparathyroidism 1

• Dosing considerations:

  • For maintenance after repletion: 200-1,000 IU daily 1
  • Avoid excessive supplementation as meta-analyses show increased risks of hypercalcemia and hypercalciuria with long-term vitamin D supplementation 5
  • Consider using the equivalent monthly dose (e.g., 50,000 IU once monthly) rather than daily dosing if adherence is a concern 1

Special Considerations

• In patients with CKD and kidney stones:

  • More careful monitoring is required as kidney function declines 1
  • For CKD stages 3-5D, vitamin D supplementation should be prescribed to correct deficiency/insufficiency but with close monitoring of calcium levels 1
  • Patients with nephrotic-range proteinuria may require higher vitamin D doses due to urinary losses of vitamin D-binding protein 1

• Risk assessment:

  • Meta-analyses suggest that while vitamin D supplementation increases risk of hypercalciuria and hypercalcemia, it does not significantly increase kidney stone formation 5, 6
  • The NHANES III data showed no significant association between serum 25(OH)D levels and prevalent kidney stone disease 6

Practical Recommendations

• Measure urinary calcium excretion before and during vitamin D supplementation in stone formers 3, 4
• Consider lower initial doses with more frequent monitoring in patients with a history of calcium stones 2, 3
• Ensure adequate hydration and moderate dietary calcium intake (800-1,000 mg/day) when supplementing with vitamin D 1
• Avoid calcium supplements when possible in patients with calcium stones who are receiving vitamin D supplementation 3, 5
• Do not use active vitamin D analogs (calcitriol, alfacalcidol, etc.) to treat nutritional vitamin D deficiency in stone formers due to higher risk of hypercalciuria 1