Clinical association with urinary glycosaminoglycans and urolithiasis

Abstract

Objectives. To determine the clinical association between urinary glycosaminoglycan (GAG) concentration and kidney stone disease. Methods. Thirty-five patients (14 women and 21 men) with a history of stone disease and 37 controls (13 women and 24 men) were evaluated for urinary GAG concentration. By using a new dye-binding assay, the total GAG concentration in the urine was measured and corrected to urinary creatinine levels (micrograms of GAG per milligram creatinine). Results. The mean urinary GAG concentration in those with stones was significantly lower (31.5 ± 2.6 μg GAG/mg creatinine) than in the controls (43.8 ± 3.8 μg GAG/mg creatinine, P = 0.01). Male patients with stones also had a significantly lower mean GAG concentration (26.1 ± 1.8) than did the female patients (39.6 ± 5.3, P = 0.009). The mean GAG concentration between ureteral (n = 13) versus renal (n = 22), single (n = 19) versus multiple (n = 16), family history (n = 11) versus no family history (n = 24), large (n = 13) versus small (n = 20), and the presence (n = 22) versus absence (n = 13) of residual stones did not show any significant differences. However, patients with recurrent stone formation (n = 21) had significantly lower mean GAG levels (26.4 ± 1.6) compared with those with single stone formation (n = 14; 39.2 ± 5.5, P = 0.01). Conclusions. Lower urinary GAG levels are more common in patients with stone formation. This may play a more determinant role in male patients and those with recurrent stone formation.