Category: Clinical Stones: Ureteroscopy

MP29-5 - Are Calcium Oxalate Dihydrate Stones Associated with Hypercalciuria?

Sun, Sep 23
2:00 PM - 4:00 PM

Introduction & Objective : Calcium oxalate (CO) stones are the most common type of renal stones and can be divided into monohydrate (COM) and dihydrate (COD). There is evidence that the mean concentration of oxalate ions is higher and in urine samples containing COM crystals vs. COD crystals and conversely a higher calcium ion concentration in urine containing COD vs. COM crystals. In this study, we differentiated COM and COD stones by 24-hour urine to describe the metabolic differences between these types of stone formers and aim to determine if there is an association between COD stones and hypercalciuria.


Methods : We retrospectively reviewed medical records of patients referred to a large tertiary clinic in New York. Patients were included in this study if stone analysis revealed the renal stones were made exclusively of COM and COD prior to medical or surgical treatment. Patients were excluded if the composition of the stones was either less than 80% COM or 80% COD. We investigated the relationships between metabolic factors, clinical characteristics, and stone composition. We used descriptive statistics, Chi-square, Fischer’s exact, and t-test to look at associations between these parameters.


Results : 124 patients were included in our study. 65% were male and the average age of participants was 57 years. On average, COD stone formers had higher Ca24 (238.5 vs 188.1, p<0.025), SSCaP (1.31 vs 0.82, p<0.003), Ca24Kg (3.1 vs 2.3, p=0.004), and Ca24Cr24 (136.4 vs 105.4, p=0.005) on 24-hr urine when compared to COM stone formers. Table 1 describes our results.


Conclusions : While COM stone formers are more likely to have hyperoxaluria, COD patients have higher urinary calcium levels than COM stone formers. This may be used to help differentiate between patients forming CO stones, may give insight into the etiology of COD stone formation, and may help guide treatment for those whose stone composition is not known.

Stephanie Purnell

Research Fellow
Icahn School of Medicine at Mount Sinai
New York, New York

Blair Gallante

Research Coordinator
Icahn School of Medicine at Mount Sinai
New York, New York

Julie Thai

Research Fellow
Icahn School of Medicine at Mount Sinai
New York, New York

William M. Atallah

Assistant Professor of Urology, Icahn School of Medicine at Mount Sinai
Icahn School of Medicine at Mount Sinai
New York, New York

William Michael Atallah, MD, MPH
Assistant Professor of Urology, Icahn School of Medicine at Mount Sinai
Assistant Professor of Urology, Elmhurst Hospital

Mantu Gupta

Chairman of Urology
Mount Sinai West and Mount Sinai St. Luke's
New York, New York

Jacob Bamberger

Research Fellow
Mount Sinai
New York, New York

Jake Bamberger, Research Fellow at Icahn School of Medicine at Mount Sinai, Department of Urology