Urinary Metabolic Disorders Associated with Urolithiasis in Cuban Pediatric Patients.

Introduction: Pediatric urinary lithiasis (urolithiasis) is an important health issue linked to urinary metabolic disorders. In the United States alone, annual costs associated with urolithiasis are $229 million for hospital admissions and $146 million for emergency care.

Objective: Identify urinary metabolic disorders in Cuban pediatric patients with urolithiasis and better understand the relationship of age, demographic and anthropometric variables to urinary metabolic disorders strongly associated with urolithiasis.

Methods: We carried out a descriptive, cross-sectional study. The study universe was comprised of Cuban patients aged 2 to 19 years with urinary lithiasis who underwent renal metabolic studies at the Dr Abelardo Buch López Nephrology Institute in Havana, Cuba, from 2008 through 2019. All data were obtained from reports of the aforementioned metabolic studies. We collected the following variables: age, sex, nutritional status, urinary volume, plasma and urinary creatine concentrations; and calcium, uric acid, oxalate and citrate urinary excretions collected during a 24-hour period. We included results of urinary cystine tests and urine mini-cultures. We obtained frequency distributions for categorical and qualitative variables and calculated means and standard deviations for quantitative variables. We also evaluated homogeneity of metabolic disorders between children and adolescents.

Results: We studied 1592 pediatric patients, of whom 67.7% (1078/1592) were adolescents. The main metabolic disorders included hypercalciuria (39.1%; 622/1592), decreased urinary flow (22.4%; 357/1592) and hypocitraturia (18.2%; 289/1592). Hypercalciuria, hypocitraturia and hyperoxaluria were more common in children, while decreased urinary flow and hyperuricosuria were more common in adolescents. Hyperuricosuria was more frequent in male patients (6.3%; 40/639 vs. 1.8%; 8/439) and had the greatest impact on lithogenesis. Hypercalciuria was more frequent in undernourished children (62.5%; 30/48) than in overweight children (21.7%; 10/46), or those with obesity (33.3%; 15/45).

Conclusions: The main metabolic disorders among Cuban pediatric patients with urinary lithiasis are: hypercalciuria, decreased urinary flow and hypocitraturia. Hypercalciuria, hypocitraturia and hyperoxaluria are more common in children, and decreased urinary flow and hyperuricosuria are more common in adolescents. Identifying urinary metabolic disorders facilitates formulation of treatment plans tailored to decreasing the likelihood of urolithiasis.