Urinary stone disease in pediatric and adult metabolic bone clinic patients

Kidney stones are increasing in the pediatric and adult populations; similarly osteoporosis is increasingly recognized in children. While kidney stone formers are known to suffer from low bone density, metabolic bone patients have not been considered a high risk population for kidney stones. Retrospective chart review of Nationwide Children’s Hospital Metabolic Bone Clinic patients from October 2009–2013. Patients were identified by ICD 9 codes for osteoporosis, osteopenia, low bone density and kidney stones. Only patients with radiologic evidence of both diseases were included.Twenty-six of 889 patients met criteria; this is equivalent to an incidence of 30 per 100,000 patients. Osteoporosis was the most frequent bone diagnosis. Males were the majority (68%). Most common secondary diagnoses: seizure (52%) and cerebral palsy (44%). Treatment: calcium (48%), vitamin D (40%), bisphosphonates (48%). The majority (75%) were non-ambulatory. Most frequent lithogenic medications: Topiramate (42%) and corticosteroids (27%). This is one of the first studies to consider metabolic bone patients as high risk for urinary stone disease. We found a higher rate of kidney stones in pediatric metabolic bone patients compared to data available for the general pediatric kidney stone population. The most common risk factor for bone and stone disease was nonambulatory status. Males were more frequently affected than females; this is the reverse of general adolescent kidney stone population. The predominance of cerebral palsy and seizure patients can be attributed to their frequency of non-ambulatory status and lithogenic medications such as Topiramate.