Improved 24-hour urine parameters associated with reduced symptomatic kidney stone recurrence

Area of Science:

• Nephrology
• Urology
• Metabolic Disorders

Background:

• On-treatment 24-hour urine testing rates are low outside specialized centers.
• Evidence linking optimized urinary parameters to reduced kidney stone recurrence is limited.

Purpose of the Study:

• To evaluate if improvements in 24-hour urine parameters correlate with decreased symptomatic kidney stone recurrence.
• To assess the predictive value of a novel 24-hour urine severity score for stone recurrence.

Main Methods:

• Prospective analysis of kidney stone patients with multiple 24-hour urine tests and initial parameter abnormalities.
• Calculation of a novel 24-hour urine severity score at initial and subsequent tests.
• Negative binomial regression to assess the impact of analyte changes on stone recurrence.

Main Results:

• Low voided volume, hypercalciuria, hyperoxaluria, hypocitraturia, and low pH were common abnormalities.
• Consistent normalization of hypercalciuria and hypocitraturia was associated with decreased recurrence (p<0.001).
• Higher initial 24-hour urine severity scores predicted increased stone recurrence; score improvement/stabilization reduced recurrence risk (p<0.001).

Conclusions:

• Consistent control of 24-hour urine parameters is linked to reduced kidney stone recurrence.
• The novel 24-hour urine composite severity score predicts stone recurrence.
• Improvements in the severity score over time indicate a decreased risk of recurrence.