Metabolic Insights From Composition-Based Analysis of Kidney Stones: A Retrospective Study of 506 Patients

Kidney stone disease is a highly prevalent condition with increasing global incidence and recurrence. The stone composition reflects underlying metabolic and biochemical alterations, and its evaluation may provide clinically relevant information for effective management.

To evaluate the distribution of stone composition in a large surgical cohort and explore its association with routinely assessed metabolic parameters and recurrence patterns.

This retrospective single-center study included 506 adult patients who underwent surgical stone removal between 2018 and 2024. The stone composition was determined using Fourier-transform infrared (FTIR) spectroscopy and classified as calcium oxalate monohydrate (COM), calcium oxalate dihydrate (COD), uric acid (UA), or a mixed type. Available serum (calcium, uric acid, glucose) and 24-hour urinary parameters (calcium, oxalate, citrate, uric acid) were evaluated. Subgroup analyses compared first-episode and recurrent stone formers.

A total of 506 patients were included in the final analysis. Calcium oxalate dihydrate (COD) was the most prevalent stone type, accounting for 307 cases (60.7%), followed by calcium oxalate monohydrate (COM) in 117 (23.1%), calcium/magnesium phosphate (CaP) in 46 (9.1%), uric acid stones in 31 (6.1%), and cystine stones in 5 patients (1.0%). The mean age of the cohort was 37.9 ± 11.4 years, and males comprised 73% of the study population. Patients with uric acid stones were significantly older than those with other stone types (p< 0.001), while body mass index did not differ significantly across stone groups (p> 0.05).

Stone composition assessed by FTIR analysis demonstrates meaningful associations with selected metabolic abnormalities and recurrence status. Rather than functioning as a standalone decision tool, composition-guided interpretation combined with comprehensive metabolic evaluation may support more informed patient follow-up and preventive counselling.