Dados do Trabalho

Título

EFFECTS OF 24-HOUR URINARY CALCIUM OXALATE SUPERSATURATION LEVELS ON STONE GROWTH AND NEW STONE FORMATION: “WHEN TO WORRY – WHEN TO NOT?”

Introdução e Objetivo

Medical management for calcium oxalate (CaOx) urolithiasis commonly focuses on reducing CaOx supersaturation (SS). Using sequential computed tomography (CT) calculated 3D stone volume in conjunction with 24-hour CaOx SS levels, we sought to define CaOx SS thresholds for stable vs. increasing stone volume.

Método

Thirty-four patients with a stone composition ≥50% CaOx and without interval stone passage or treatment, underwent 3D segmentation renal stone volume determinations based on two sequential CT scans a median of 406 days apart (range 98 to 2563 days) with at least 2 corresponding 24-hour urine analyses (i.e., Litholink™), obtained within 4 months of each CT scan.  Increased stone volume was defined as ≥15% increase from baseline. T test and logistic regression were performed to evaluate CaOx SS levels among patients with and without a change in stone volume.

Resultados

An increase in stone volume occurred in 26 patients (76.5%); these individuals had a CaOx SS that was significantly higher for mean of baseline (SS 6.96 vs. 4.45), average (SS 6.79 vs. 4.12) and maximum (SS 9.20 vs. 5.45) (Figure 1); overall, there was a positive relationship between increase in CaOx SS and increased stone volume (p = 0.043, p = 0.014, p = 0.024, respectively).   

Conclusão

Among patients with CaOx kidney stones, 24-hour urine CaOx SS was positively associated with an increase in stone volume.  CaOx SS below 3 appears favorable, whereas levels over 5 are concerning. Each additional point rise in average CaOx SS was associated with a three-fold higher risk of increased stone volume.