Retrospective analysis of patients with urinary system stone disease and evaluation of urinary calcium citrate ratio

Background: Urinary tract stone disease is a disease characterized by the formation of stones in the kidneys, ureters and bladder in which many factors such as hereditary, environmental, nutritional and medications play a role. Its prevalence has increased worldwide in the last 20 years and urinary system stones are an important health problem. There are studies showing that the prevalence of urinary tract stone disease in childhood is between 5-10% in recent years. However, the prevalence of urinary tract calculi may vary according to regional differences, sample sizes and age groups. Childhood urinary tract stone disease has a high recurrence rate and is an important cause of morbidity as it causes end-stage renal disease. Since urinary system anomalies and metabolic abnormalities often accompany stone disease, early recognition of childhood urinary tract stone disease and screening for underlying metabolic factors and urinary system anomalies are important in reducing morbidity and preventing progression to chronic kidney disease. Materials and Methods: Between January 2012 and December 2022, a total of 989 patients between 0 and 18 years of age who were admitted to the Pediatric Nephrology outpatient clinic of Başkent University Ankara Hospital and diagnosed with urinary tract stone disease were retrospectively analyzed. Among 989 patients, 325 patients with both calcium and citrate in spot or 24-hour urine tests and concurrent urinary tract US were included in the study. Demographic data, medical history, laboratory data, radiologic findings and treatments were evaluated. The calcium citrate ratio in spot and 24-hour urine was investigated statistically as a new marker for urinary system stone disease. Results: Of the 325 patients included in the study, 51,1% were male. The median age at diagnosis was 29 months. 57,9% of the patients had a family history of calculi. It was observed that younger children presented with reasons such as restlessness and UTI at first presentation, whereas older children presented with reasons such as hematuria and vomiting (p<0.05). No significant difference was found between genders in terms of ca/sit in urine (p>0.05). In our study, the median ca/sit ratio in spot urine was 0,18 (0,01-3,29) mg/mg in patients without stones and 0,31 (0,01-3,47) mg/mg in patients with stones. Twenty-four-hour urine ca/sit ratio was 0,23 (0,02-5,73) mg/mg in patients without stones and 0,32 (0,01-6,54) mg/mg in patients with stones. In our study, spot and 24-hour urine ca/sit ratios were significantly higher in children with stone disease compared to children without stone disease (p<0.05). Values higher than 0,235 for the ca/cite ratio in spot urine were found to be significant in terms of stone risk. In patients with stones, the most common location of the stones was renal pelvis (75,8%). There were no patients with stones in the bladder. The stones were located on the left side in 80 patients (40,4%) and bilaterally in 75 patients (37,8%). 78,3% of the stones were less than 5 mm in size. The most common treatment modality was stone preventive medical therapies. Discussion: In our study, in patients with urinary system stones, both spot urine and 24-hour urine ca/cit ratio were found to be significantly higher than in patients without stones. In addition, values higher than 0,235 in spot urine are considered significant in terms of stone risk. The use of spot urine ca/cit ratio as a screening test in patients with stone risk may be a useful marker. Further prospective, randomized controlled studies with a larger number of cases are needed. Keywords: Child, urinary stone disease, urine calcium citrate ratio, urolithiasis