Risk factors for urolithiasis in gastrostomy tube fed children: a case-control study.

BACKGROUND AND OBJECTIVE Pediatric patients who are fed primarily via gastrostomy tube (G-tube) may be at increased risk for urolithiasis, but no studies have specifically examined risk factors for stones in this population. We aimed to determine clinical differences between G-tube fed (GTF) patients with and without stones, in hopes of identifying modifiable factors associated with increased risk of urolithiasis. METHODS We conducted a retrospective case-control study, matching GTF patients with urolithiasis (cases) to GTF children without urolithiasis (controls) based on age (±1 year) and gender. Bivariate comparisons and matched logistic regression modeling were used to determine the unadjusted and adjusted associations between relevant clinical factors and urolithiasis. RESULTS Forty-one cases and 80 matched controls (mean age 12.0 ± 6.5 years) were included. On bivariate analysis, factors associated with stone formation included: white race, urinary tract infection (UTI), topiramate administration, vitamin D use, malabsorption, dehydration, 2-year duration with G-tube, and whether goal free water intake was documented in the patient chart. On regression analysis, the following factors remained significant: topiramate administration (odds ratio [OR]: 6.58 [95% confidence interval (CI): 1.76-24.59]), UTI (OR: 7.70 [95% CI: 1.59-37.17]), and <2 years with a G-tube (OR: 8.78 [95% CI: 1.27-52.50]). CONCLUSIONS Our findings provide a preliminary risk profile for the development of urolithiasis in GTF children. Important associations identified include UTI, topiramate administration, and shorter G-tube duration, which may reflect subclinical chronic dehydration. Of these, topiramate use represents the most promising target for risk reduction.