The Effect of Geographic Region on Stone Composition and Treatment Outcomes for Urolithiasis in Kyrgyzstan

Background — Data on urolithiasis characteristics and treatment outcomes in high-elevation areas are limited. Using computed tomography (CT), we assessed whether kidney stone composition, CT density, and minimally invasive treatment outcomes differ between residents of Kyrgyzstan living in mid-elevation and high-elevation areas. Methods — This multicenter retrospective study included adults (18-75 years) treated for urolithiasis (2020-2023) and stratified by their residence into mid-elevation (n=88) and high-elevation (n=51) groups. Kidney stone characteristics were assessed using non-contrast CT scan (location, size, and density in Hounsfield units), as well as laboratory compositional analysis and X-ray spectral analysis. The primary outcome was stone freedom after the initial procedure, with residual fragments >4 mm considered treatment failure. Outcomes were compared by region and treatment method. Results — A total of 139 patients (74.8% men; mean age 55.9 years) were included in the study, with no significant differences in baseline data between the groups. Intrarenal stone location varied: stones in the renal pelvis, ureteropelvic junction, and lower and middle renal calyces were more common in residents of mid-elevation areas, while laterality was similar. Oxalate (48.7%) and phosphate (27.7%) stones predominated, with a nonsignificant trend toward an increase in the number of phosphate stones in high-elevation areas (p=0.663). Calcium oxide was the dominant element and correlated strongly with CT density (r=0.71, p