Category: Clinical Stones: Medical Management

MP10-16 - Uric Acid Nephrolithiasis: Long-term Metabolic and Clinical Outcomes from a Single Institution

Fri, Sep 21
2:00 PM - 4:00 PM

Introduction & Objective :

Despite rising prevalence of uric acid (UA) nephrolithiasis, longitudinal studies have not been performed to examine long-term metabolic and clinical outcomes in these individuals.

Methods : We retrospectively identified all UA stone formers (SF) deemed stone free by computed tomography (CT) after a stone procedure and grouped them by %UA stone composition: 30-89% (mixed), 90-100% (pure). Baseline demographics and metabolic evaluations were documented. Outcomes in patients who remained in our system ≥6 months and had CT follow-up imaging were recorded, including medication adherence, urine pH, stone recurrence, and need for surgical stone intervention.

Results :

Inclusion criteria was met in 113 UASF (52% pure; 48% mixed). At a median of 24 months, 53/113 (47%) UASF maintained follow-up. Of these, 28/53 (53%) elected medication as part of a prevention plan, 14 (26%) elected dietary therapy without medication, and another 11 (21%) were either intolerant or non-adherent to medical therapy. Over study duration, those without medical therapy (n=25) had similar urine pH and stone recurrence rates as adherent patients (n=28), regardless of %UA composition (Table 1). Adherent patients, however, had smaller CT stone recurrences (6.3 versus 12.5 mm, p=0.02) and were less likely to require stone surgery compared to those without therapy (0% versus 28%, p<0.01).

Conclusions :

In our UASF cohort, adherence to medical therapy did not result in urine pH differences but did reduce stone recurrence size and need for surgical interventions compared to those without therapy. These findings highlight the protective role of potassium citrate in stone disease and areas for improvement in UA stone prevention strategies.

Vincent G. Bird

Professor of Urology
University of Florida College of Medicine, Department of Urology
Gainseville, Florida

Dr. Vincent G. Bird is currently Professor in the Department of Urology, Chief of the Division of Minimally Invasive Surgery, the endourology and minimally invasive surgery fellowship program co-director, and associate program director of the residency program in the Department of Urology at the University of Florida College of Medicine. Dr. Bird completed his fellowship training in robotics, laparoscopy and endourology at the University of Iowa Hospitals and Clinics. At the conclusion of his fellowship, Dr. Bird was recognized for excellence in clinical science by the Endourological Society for research relating to patterns of treatment for urinary stone disease.
Dr. Bird received his undergraduate education at Boston University, and attended medical school at the State University of New York, Stony Brook, where he received his medical degree with distinction in research and was also awarded for his work involving cellular processes related to cancer and inflammation. Dr. Bird then completed his general surgical and urological training at the University of Miami. Currently, his clinical practice focuses on renal surgery for urinary stone disease, renal obstruction, and renal cancer, while his clinical and basic science research focus is on the treatment of a variety of renal conditions. He also has publications and interests relating to urologic imaging. He has contributed publications on treatment of urinary stone disease with newly developed technologies.
Dr. Bird is also an active member of the American Urological Association, Southeastern Section of the American Urological Association, Endourological Society, and past president of the Florida Urological Society. Dr. Bird has held a number of positions within the Florida Urologic Society, serving two terms as scientific director as well as secretary treasurer. He serves as a reviewer for a number of Urology based journals.

Nitin Sharma

Clinical Fellow
University of Florida College of Medicine, Department of Urology
Chicago, Illinois

Benajamin K. Canales

University of Florida College of Medicine, Department of Urology
Gainesville, Florida

Stanislav Yuzhakov

Gainesville, Florida

Shahab Bozorgmehri

University of Florida College of Medicine, Department of Epidemiology
Gainesville, Florida

Brandon Otto

University of Florida College of Medicine, Department of Urology
Gainesville, Florida