Clinical features and outcomes of symptomatic urinary stone disease: An analysis according to stone compositions

Background The incidence of urinary stone disease is increasing, and these patients are at greater risk for various kidney complications. Given its heterogeneity and potential clinical implications, we investigated the baseline characteristics and clinical outcomes of symptomatic stone disease according to stone compositions. Methods This was a single-center, retrospective study that analyzed symptomatic urinary stone disease patients with known stone compositions from 2002 to 2020. Patients were grouped into three categories: calcium-containing, urate, and struvite stones. Baseline characteristics, prevalence of diverse comorbidities, concurrent acute kidney injury events, long-term kidney function deterioration, and mortality were analyzed. Results Calcium-containing stones were the most common type. Patients with urate stones were significantly older, predominantly male, and more likely to have various comorbidities and low urinary pH. Calcium excretion was significantly higher in patients with calcium-containing stones, while the excretion of other components was comparable across all stone compositions. The incidence of acute kidney injury in symptomatic urinary stone disease patients was 35.3%. Of note, urate and struvite stones were independently associated with concurrent acute kidney injury. An eGFR decline of more than 30% was observed in 5.7% of the patients, with the highest rates among patients with urate stones. Older age, female sex, higher baseline serum creatinine level, and concurrent acute kidney injury episodes, but not stone composition, were independently associated with subsequent kidney function deterioration. Conclusions In symptomatic urinary stone disease, concurrent acute kidney injury episodes, older age, female sex, and lower baseline kidney function were independent associated with progressive kidney function deterioration, regardless of stone composition.