An Important Risk Factor Affecting Hypercalciuria in Children: Vesicoureteral Reflux

Abstract

Introduction A large number of genes and environmental factors, like dietary habits, play a role in the development of hypercalciuria in children. In this study, we aimed to determine the effects of the presence and grade of vesicoureteral reflux (VUR) on hypercalciuria status in children. Materials and Methods Data for 165 patients who admitted to the Pediatric Urology Department were retrospectively analyzed. The patients were composed of following four different groups: (1) urinary stone patients, (2) VUR patients under follow-up, (3) corrected VUR patients, and (4) control. The demographic features, clinical data, and laboratory tests for the groups were compared. Results The mean age of the patients was 100.6 ± 54.69 months and the female/male ratio was 79:86. The mean urinary calcium/creatinine (UCa/Cr) excretion and the frequency of high UCa/Cr ratios in the corrected VUR group were similar to those in the control group (p = 0.375 and 0.965, respectively). In contrast, the mean UCa/Cr excretion and frequency of high UCa/Cr ratios in the urinary stone and follow-up VUR groups were significantly higher than those in the corrected VUR group (p < 0.001, < 0.001, 0.003, and 0.029, respectively). The mean UCa/Cr excretion and frequency of high UCa/Cr ratios in the follow-up VUR group were similar to those in the urinary stone group (p = 0.323 and 0.425, respectively). In the follow-up VUR group, although reflux laterality had no effect on the UCa/Cr ratios (p = 0.180 and 0.108, respectively), the mean and frequency of high UCa/Cr ratios were higher in high-grade reflux cases (p < 0.001 and p = 0.042, respectively). Conclusion Both the mean UCa/Cr ratio and the rate of hypercalciuria in the corrected reflux group were significantly lower than the corresponding values in the follow-up VUR and urinary stone groups. Further, the follow-up VUR patients had similar urinary calcium excretion levels as the stone patients. VUR treatment is associated with a decrease in urinary calcium excretion to the normal population level. A positive correlation between reflux degree and calcium excretion was observed.

Vesicoureteric reflux and urolithiasis in the paediatric population: causality, correlation or no connection at all?

“…table 1). This bias, named in the paper of Haberal et al [4], but not discussed in any of the articles, is relevant, because in young children higher Ca/Cr-ratios are physiological [29]. In our study, the majority (89%) of patients with calcium stones had no VUR, thus not supporting a major role of VUR for calcium stones, either.…”

“…Incidence of childhood urolithiasis varies greatly between different regions with multiple factors contributing to stone formation, including anatomic anomalies. [1] Some publications mention VUR as risk factor or recommend that "investigation of urolithiasis in children should include voiding cystography" [2][3][4][5].…”

“…A stone was diagnosed in 9 patients (0.5%, see table 2b, 3 pts are identical with pts no 1, 2, and 4 from group 1). In 6/1758 pts VUR was found to have a possible, likely or evident impact on stone formation (pts no4,9,10,11,12,14), i.e. 0.34%.…”

“…Above that, VUR has been attributed to be a metabolic risk factor for Calcium stone formation. Several studies found elevated calcium/creatinine ratios (Ca/Cr) in urine of children with VUR [2][3][4]. But the VUR groups are signi cantly younger than the controls in all of those publications (suppl.…”

“…When looking at both groups together, VUR is closely correlated to infection-stone formation in 7 children (pts no 4,7,9,10,11,12,14). But more than half of those (4/7) have additional disorders related to stone formation and infection (FPIES, hyperoxaluria, neurogenic bladder in 2), getting VUR in the background and leaving only 3 of 1831 patients (0.16%) with VUR as exclusive risk factor.…”