Back to Program


Vitamin D Deficiency May Be Predicted in Patients with Elevated Parathyroid Levels and Normocalcemic Hypercalcuria
Liza Aguiar, MD, George Haleblian, MD, Gyan Pareek, MD.
Brown Medical School, Urology, Providence, RI, USA.

BACKGROUND: A metabolic stone evaluation (MSE) in patients at risk for recurrent stone disease normally includes serum chemistry tests and 24 hr urine studies. Interestingly, there is little uniformity amongst the urologic community on the specifics of the metabolic profile to be studied in these patients. At our institution, the MSE has been altered to include analysis of all constituents involved with calcium metabolism. We report on the value of such an evaluation and illustrate the importance of a thorough work-up in detecting Vitamin D deficiency.
METHODS: A total of 850 patients underwent a MSE over a 4 year period (8/2005 to 8/2009). Of these patients, we analyzed those who underwent a complete calcium profile and a 24 hour urine collection, a MSE technique utilized over the last 2 years (8/2007 to 8/2009). The evaluation included serum calcium, parathyroid hormone (PTH), phosphorous and Vitamin D25 levels and a 24 hour urine collection. Patients with abnormal parameters in any of the calcium profile parameters were further studied with the relationship of total calcium, ionized calcium, parathyroid hormone, and vitamin D assessed. Descriptive statistical analysis of the data was carried out to assess various trends in the profiles.
RESULTS: A total of 850 patients underwent a MSE at our institution since inception of our preventive care protocol. Of these, 200 were subject to a modified protocol involving a thorough calcium profile analysis along with the 24 hour urine collection. Of the 200 patients, low vitamin D25 levels were identified in 28 (14%) of patients. The mean Vitamin D level in these patients was 20 (range:7.4 - 31). The PTH, ionized calcium and 24 hour urine chemistries were assessed in this subgroup. Of the 28 patients 14 (50%) had elevated serum PTH levels, with a mean PTH level of 84 (range: 70-102). Of the patients with low Vitamin D25 levels and elevated PTH levels, 14 (100%) had hypercalcuria (mean: 302 mg, range: 280mg to 340mg) and normal serum calcium levels (mean 9.3, range: (8.6 to 10.1).
CONCLUSIONS: Vitamin D deficiency may be predicted in stone patients with normocalcemic, elevated PTH, and isolated hypercalcuric profiles. The role of vitamin D and stone formation needs further elucidation. Vitamin D25 should be included in all MSE’s in high risk stone formers as it may be present in up to 14% of patients undergoing a MSE.


Back to Program