Contemporary kidney stone analysis composition among U.S. adults and children in a large reference laboratory setting

To provide updated population-level data on stone composition by characterizing changes in the prevalence of kidney stone composition by patient age, gender, and geographic location using data from a large tertiary stone analysis laboratory.

The [redacted for anonymity] receives kidney stone specimens for analysis by infrared spectroscopy. All stones submitted over a 12-month period (December 2022-November 2023) are included in this report. Stone characteristics were analyzed together with patient age, gender, and geographic location.

85,273 stones were analyzed. The rate of stone submission did not vary significantly by month (p = 0.37). Stones were more commonly from the male (55.5%) versus female patients. However, women made up a greater proportion of stone submissions aged 12-50 (53.9%). Individuals < 30 years of age made up 7.3% of stone submissions and had a significantly higher incidence of calcium phosphate stones (p < 0.05). Rare drug or metabolite stone submissions (0.04%) included xanthine, guaifenesin, triamterene, atazanavir, and N4-acetyl-sulfamethoxazole.

In contrast to previous findings, no difference in the prevalence of various stone types was observed by month of year. This may reflect evolving climate patterns, and warrants continued attention. The gender gap between men and women for stone formation is seen to be closing, with women submitting the majority of stones from individuals less than 50 years old. Whether this trend will persist as these women age in coming decades will be an important area of future study of stone epidemiology.