title: Risk factors for urolithiasis in gastrostomy tube fed children: a case-control study.
abstract: 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.
authors.affiliation: Division of Gastroenterology and Nutrition, Boston Children’s Hospital, Boston, MA, USA. emilie.johnson@childrens.harvard.edu
authors.forename: Emilie K
authors.initials: EK
authors.lastname: Johnson
authors.forename: Jenifer R
authors.initials: JR
authors.lastname: Lightdale
authors.forename: Caleb P
authors.initials: CP
authors.lastname: Nelson
mesh_terms: D000293:Adolescent; D000367:Age Factors; D000927:Anticonvulsants / Q000009:adverse effects / Q000627:therapeutic use; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D002908:Chronic Disease / Q000628:therapy; D015331:Cohort Studies; D004750:Enteral Nutrition / Q000009:adverse effects*; D005260:Female; D005632:Fructose / Q000009:adverse effects / Q000031:analogs & derivatives / Q000627:therapeutic use; D005774:Gastrostomy; D006801:Humans; D008297:Male; D012189:Retrospective Studies; D012307:Risk Factors; D012737:Sex Factors; D000077236:Topiramate; D052878:Urolithiasis / Q000175:diagnosis / Q000209:etiology*
chemical_list: D000927:Anticonvulsants; D000077236:Topiramate; D005632:Fructose
keywords: G-tube; case-control study; complications; feeding difficulties; gastrostomy; percutaneous endoscopic gastrostomy (PEG) tube; risk factors; urolithiasis