Changes in Urinary Lithogenic Features Over Time in Patients With Urolithiasis

ObjectivesTo assess the changes and sex-specific differences in urinary metabolic risk factors with time.MethodsWe performed a retrospective analysis of 619 patients with first-time calcium stone formation (SF) with complete metabolic assessments, who had been diagnosed and treated from 1994 to 2007 at our institution. Patients with SF were categorized into 2 groups according to the date of initial diagnosis: group 1 (1994-1999, n = 353 [57.0%]) and group 2 (2000-2007, n = 266 [43%]).ResultsThe incidence of obesity was greater in group 2 than in group 1, and this difference was statistically significant among male patients with SF. The urinary pH and total urine volume were lower and the excretion of uric acid was greater in group 2 than in group 1. The incidence of metabolic abnormalities such as low urine volume was more common in group 2 than in group 1. The incidence of hyperuricosuria was increased in male patients with SF in group 2 compared with that in the men in group 1. However, no significant differences were found in the incidence of hyperuricosuria in the female patients with SF between groups 1 and 2.ConclusionsThe pattern of urinary lithogenic factors in Korean patients with SF has changed with time. Hyperuricosuria has become more prevalent in recent years. We found a high prevalence of hyperuricosuria in men, which might have been due to the increased incidence of obesity in this subgroup.