The incidence of calcium oxalate stones in varions metabolic conditions

Introduction. The lithogenesis of calcium oxalate stones largely depends on specific metabolic disturbances, which develop under the influence of various endogenous, exogenous, and social factors. To prevent recurrence of the disease, according to the Russian Ministry of Health's clinical guidelines for «Urolithiasis», it is necessary to focus on the levels of lithogenic substances in the blood and daily urine. However, these standard values considered without taking into account their potential to cause the development of urinary stones of a specific chemical composition. Determining such laboratory criteria may help clinicians more reliably prevent the development of urolithiasis. The aim of this study was to investigate the metabolic conditions underlying the formation of calcium oxalate stones. Materials and methods. Data from 263 patients (145 men, 118 women) with calcium oxalate stones (>50% of stone composition) aged 18 to 78 years, treated at the N.A. Lopatkin Research Institute of Urology and Interventional Radiology from 2019 to 2023 analyzed. Biochemical analysis of 24-hour urine used to determine levels of calcium, uric acid, phosphorus, magnesium, and pH. Each dependent variable ranked by interval. Results. The greatest lithogenic effect on the formation of calcium oxalate stones observed when the threshold values are exceeded: calcium 4.8-5.1 mmol/day, uric acid 3.48-3.87 mmol/day (non-linear graph), phosphates 34.4-40.2 mmol/day, magnesium 5.4-6.4 mmol/day and urine pH 4.8-5.5. The following excretion parameters were less significant: calcium up to 3.8-4.35 mmol/day, uric acid - 0.7-1.71 mmol/day, phosphates - up to 34.2 mmol/day, magnesium 0.20-1.49 mmol/day and urine pH 7.1-9.0. Conclusion. The most significant metabolic conditions for calcium oxalate stone formation are: urinary calcium excretion above 5.8-5.1 mmol/day and urine pH less than 6.0. The highest incidence of wewellite and weddelite observed at pH values of 4.8-5.5 and 5.6-6.0, respectively. Given the influence of urine pH on calcium excretion, correction of urine pH plays a key role in the prevention of calcium oxalate lithogenesis.