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Calcitriol, calcium supplements increase nephrocalcinosis risk in hypoparathyroidism
Risks for nephrocalcinosis and decreased estimated glomerular filtration rate were found among children with hypoparathyroidism who were treated with calcitriol and calcium supplements, according to recent study findings published in The Journal of Clinical Endocrinology & Metabolism.
“Given that hypoparathyroidism is a chronic medical condition requiring long-term medical treatment, the presence of alterations in renal function in childhood could signify a risk for future health,” the researchers wrote.
Jennifer Harrington, MBBS, FRACP, PhD, and colleagues from The Hospital for Sick Children and the University of Toronto evaluated 29 children with hypoparathyroidism (52% boys) to determine the prevalence and predictors for renal abnormalities among them. The main outcome measures included the presence or absence of nephrocalcinosis and eGFR. Follow-up was conducted for a mean duration of 7.4 years.
Lower serum total calcium was associated with older age at the final visit and longer duration of disease (P < .01), and a higher degree of hyperphosphatemia was associated with a greater degree and duration of hypocalcemia (P < .001 for both).
The area under the curve (AUC) for serum calcium concentrations greater than 9.8 mg/dL (P = .04) and higher calcitriol dose (P < .01) were positively associated with higher urinary calcium excretion. Overall, 38% of participants were diagnosed with nephrocalcinosis, and the greatest predictors were the degree of relative hypercalcemia and hyperphosphatemia (P < .01).
All participants had eGFR levels greater than 60 mL/min/1.73 m2; 45% of them had eGFR between 60 mL/min/1.73 m2 and 90 mL/min/1.73 m2. No difference in eGFR was found between participants with and without nephrocalcinosis (P = .6). Male sex (P = .006) and greater proportion of time with a total calcium greater than 9.6 mg/dL (P = .006) were the greatest predictors for lower eGFR.
“This study provides new insights into the understanding of the natural history of potential renal complication associated with hypoparathyroidism in childhood,” the researchers wrote. “We observed that there is an early mild impairment to renal function that starts during childhood and which, in concordance with longitudinal studies in adults with hypoparathyroidism, may progress to chronic renal disease in adulthood. It is, therefore, imperative to start tight control of serum calcium and phosphate concentrations early after diagnosis with careful monitoring for the early development of nephrocalcinosis.” – by Amber Cox
Disclosure: The researchers report no relevant financial disclosures.