Investigating the Prevalence of Hypercalciuria in Children Aged 2–16 Years With Asymptomatic Microscopic Hematuria in 2020 in Tehran Children's Medical Center

The prevalence of hypercalciuria in children is 3%-10% globally and up to 35% in the United States. Hypercalciuria in children has many presentations; it causes different metabolic disorders and can negatively affect a child's growth. It also increases the risk of low bone mineral density and urinary tract infections. In addition, it is the most widespread cause of persistent microscopic hematuria. Changes in the diet and medications in cases of advanced stage can be useful to prevent further complications. This study aimed to determine the prevalence of hypercalciuria and to investigate its relationship with different factors in children aged 2-16 years with asymptomatic microscopic hematuria in 2020 in the Children's Medical Center hospital. This retrospective cross-sectional study was performed in a population of children aged 2-16 years old with asymptomatic microscopic hematuria who were referred to the Children's Medical Center clinic in 2020. Data such as age, sex, serum creatinine level, and proteinuria were extracted from the patient's medical records, and their relationship with hypercalciuria was analyzed using logistic regression analysis. According to the inclusion criteria, 166 children with asymptomatic microscopic hematuria (72 boys and 94 girls) were included in this study. The prevalence of hypercalciuria (ratio of random urine calcium to creatinine more than 0.2) in these patients was estimated at 25% with a confidence interval of 18%-32%. In order of prevalence, the most common conditions accompanying microscopic hematuria were kidney stones, urinary tract infections, and proteinuria. The age of patients with hypercalciuria was 2 years younger on average. Each year of age increase and every 5 years of age increase between the ages of 2 and 16 years reduced the chance of hypercalciuria in this category of patients by 12% and 45%, respectively. Our findings also showed that children with a positive history of kidney stones were about 2.2 times more likely to have hypercalciuria than their counterparts, which is considered a medium effect size. Our results showed that hypercalciuria in children with hematuria is significantly related to younger age and a positive history of kidney stones.