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Management of pediatric hypoparathyroidism carries renal abnormality risks
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MONTREAL — The management of pediatric hypoparathyroidism carries risks for complications such as renal abnormalities, according to research presented here at the annual meeting of the Canadian Pediatric Endocrine Group.
“The rationale for the study is that this has been studied in adults, but no longitudinal studies in pediatric cohorts have been done,” said Isaac Levy, MD, a fellow in pediatric endocrinology at the Hospital for Sick Children in Toronto.
Retrospective research in adult patients with permanent hypoparathyroidism has demonstrated a high rate of nephrocalcinosis and abnormal renal function, but there is an absence of follow-up studies in pediatric patients with hypoparathyroidism, Levy said.
Levy and colleagues retrospectively identified 22 patients with permanent hypoparathyroidism who were seen at least once by the hospital’s endocrine department. The patients included in the review were younger than 18 years and had disease persisting more than 1 year. Patients had various etiologies of their hypoparathyroidism, including DiGeorge syndrome, idiopathic and post-surgical hypoparathyroidism.
Investigators sought to determine whether nephrocalcinosis, renal stones or decreased estimated glomerular filtration rate was associated with hypoparathyroidism.
The mean duration of follow-up was 9 years, and the age range at the diagnosis was 0 to 14.7 years. The mean dose of calcitriol was 0.02 mcg/kg/day, and the mean dose of calcium supplements was 32.4 mg/kg/day.
Researchers found the prevalence of nephrocalcinosis to be 41% in this sample, and it was more frequent in patients who were treated with higher doses of vitamin D analogs and had hypocalcemic and hypercalcemic episodes. The average urinary calcium-to-creatinine ratio was 0.7, and the eGFR was 132.4 mL/minute/1.73m2. Researchers found no link between the presence of nephrocalcinosis and eGFR.
The prevalence of nephrocalcinosis points to the potential effect that vitamin D analogs, in particular, have on renal function, even in pediatric patients.
“This is underlining the need for the administration of the lowest possible therapeutic dose” of vitamin D analogs, Levy said. “We did not find a relationship between different doses and the development of nephrocalcinosis.”
Given the sample size, investigators were unable to find a dose-dependent effect of therapy in terms of the complication of nephrocalcinosis.
“If we had a larger sample, we could probably be able to stratify according to the doses and compare the outcomes,” Levy said.
A prospective study would be required to determine the effect of different doses of vitamin D analogs on renal function. – by Louise Gagnon
For more information:
Levy I. Oral abstract 6. Presented at: Canadian Pediatric Endocrine Group 2014 Scientific Meeting; Feb. 20-22, 2014; Montreal.
Disclosure: Levy reports no relevant financial disclosures.