Metabolic risk factors and urinary stone formation. Study VIII: Lithogenic properties of urine acidity in men and women.
Authors:   clinical laboratory diagnostic group of scientific laboratory department, N. Lopatkin Scientific Research Institute of Urology and Interventional Radiology – Branch of the National Medical Research Centre of Radiology of the Ministry of Health of Russian Federation, Golovanov S.A. ,   Moscow, Russia, Prosyannikov M.Yu. ,   the department of N. Lopatkin Scientific Research Institute of Urology and Interventional Radiology – branch of the National Medical Research Centre of Radiology of Ministry of health of Russian Federation; Moscow, Russia, Sivkov A.V. ,   N. Lopatkin Scientific Research Institute of Urology and Interventional Radiology – Branch of the National Medical Research Centre of Radiology of the Ministry of Health of Russian Federation; Moscow, Russia, Anokhin N.V. ,   the Department of urolithiasis of N. Lopatkin Scientific Research Institute of Urology and Interventional Radiology – Branch of the National Medical Research Radiological Centre; Moscow, Russia, Voytko D.A. ,   N. Lopatkin Scientific Research Institute of Urology and Interventional Radiology – branch of the National Medical Research Centre of Radiology of Ministry of health of Russian Federation; Moscow, Russia, Drozhzheva V.V. ,   Laboratory Department of N. Lopatkin Scientific Research Institute of Urology and Interventional Radiology – Branch of the National Medical Research Centre of Radiology of the Ministry of Health of Russian Federation; Moscow, Russia
Published: February 2024

Introduction. Urine acidity is an important factor that can actively modulate the process of stone formation in the kidneys, which allows using this indicator to use this indicator to assess the risk urinary stone formation and control the result of anti-relapse treatment in patients with urolithiasis (UL). There are gender differences in the prevalence of UL, which may be related to differences in urine acidity. In this study, the effect of varying degrees of pH urine on metabolic parameters and the frequency of detection of urinary stones of various chemical compositions was studied in men and women with UL. Materials and methods. We examined 982 patients with ICD (439 men and 543 women aged 18 to 79 years). To assess the lithogenic activity of uricosuria in men and women with UL, the pH values of morning urine were distributed in ascending order and divided into several groups. In each of the ranges, the percentage distribution of types of urinary stones and biochemical parameters of urine and blood were determined. Results. At urine pH of 5.1-6.5, men have higher calciuria and are more prone to oxalate stone formation, which is 1.5-2.2 times more active in them than in women (p <0.05). In contrast to men, the urinary pH level of women had a greater effect on the frequency of detection of oxalate stones, which decreased by 75.9% with a urine pH of 5.5-5.9 and higher, and was accompanied by a 33.3% decrease in calciuria (p <0.05). Uric acid lithogenesis was more dependent on changes in the pH of urine than on the activity of urocosuria. The frequency of formation of uric acid stones was inversely correlated with the pH of urine in men (r=-0.833, p=0.0102) and women (r=-0.929, p=0.0009). With a decrease in the pH of urine below 6.0, the incidence of uric acid stones in women increased by 5.76 times (p<0.0001), and in men by 1.91 times (p=0.0087). Active phosphate lithogenesis in women did not depend on the level of phosphate excretion, which was 25.5-39.7% lower than in men and progressively decreased with increasing urine pH values (p<0.00029). When the urine pH is higher than 5.9, women have a significantly increased risk of developing calculi from carbonatapatite compared to men (p=0.0005). Struvite lithogenesis increased with urine alkalinization and was more pronounced in women than in men (p=0.043). Comparison of age groups did not reveal any differences in the acidity of morning urine between men and women, however, in contrast to men, a noticeable predominance of the proportion of women with carbonatapatite stones was observed in the groups of patients older than 49 years. Conclusion. Shifts in the pH of urine can change the nature and direction of lithogenesis in men and women in different ways and are not always associated with the excretion of certain metabolic factors involved in stone formation. Gender features of the lithogenesis of various types of stones in conditions of different acidity of urine should be taken into account when conducting personalized metaphylaxis of urolithiasis.