Metabolic Characteristics and Risks Associated with Stone Recurrence in Korean Young Adult Stone Patients.

PURPOSE: The aim of this study was to assess the metabolic characteristics and risks of stone recurrence in young adult stone patients in Korea.

PATIENTS AND METHODS: The medical records of 1532 patients presenting with renal or ureteric stones at our stone clinic between 1994 and 2015 were retrospectively reviewed. Patients were grouped according to age (young adult, 18-29 years; intermediate onset, 30-59 years; old age, ≥60 years) at first presentation, and measurements of clinicometabolic characteristics and risks of stone recurrence were compared.

RESULTS: Overall, excretion of urinary stone-forming substances was highest in the intermediate onset group, followed by the young adult and old age groups. Importantly, excretion of urinary citrate was lowest in the young adult group. Kaplan-Meier analyses identified a significant difference between the three age groups in terms of stone recurrence (log rank test, p < 0.001). Multivariate Cox regression analyses revealed that age at first stone presentation was an independent risk factor for stone recurrence. Urinary citrate excretion was an independent risk factor for stone recurrence in young adult stone patients.

CONCLUSIONS: Younger age (18-29 years) at first stone presentation was a significant risk factor for stone recurrence, and urinary citrate excretion was an independent risk factor affecting recurrence in this group. Metabolic evaluation and potassium citrate therapy should be considered for young adult stone patients to prevent recurrence.