Nephrocalcinosis, Renal Dysfunction, and Calculi in Patients With Primary Hypoparathyroidism on Long-Term Conventional Therapy.

CONTEXT: There are concerns about the long-term safety of conventional therapy on renal health in patients with hypoparathyroidism. Careful audit of these would help comparisons with upcoming parathyroid hormone therapy.

OBJECTIVE

We investigated nephrocalcinosis, renal dysfunction, and calculi, their predictors and progression over long-term follow-up in patients with primary hypoparathyroidism (PH).

DESIGN AND

SETTING

An observational study at a tertiary care center was conducted.

PARTICIPANTS AND

METHODS

A total of 165 PH patients receiving conventional therapy were evaluated by radiographs, ultrasonography, and computed tomography. Their glomerular filtration rate (GFR) was measured by Tc-99m-diethylenetriamine penta-acetic acid clearance. Clinical characteristics, serum total calcium, phosphorus, creatinine, hypercalciuria, and fractional excretion of phosphorus (FEPh) at presentation and during follow-up were analyzed as possible predictors of renal complications. Controls were 165 apparently healthy individuals.

RESULTS

Nephrocalcinosis was present in 6.7% of PH patients but not in controls. Patients younger than 15 years at presentation and with higher serum calcium-phosphorus product were at higher risk. Nephrocalcinosis showed no significant association with cataract and intracranial calcification. Prevalence of renal calculi was comparable between hypoparathyroid patients and controls (5% vs 3.6%, P = .58). Fourteen percent of patients had a GFR less than 60 mL/min/1.73 m2. Increased FEPh during follow-up was the significant predictor of low GFR. Nephrocalcinosis developed in 9% of patients over 10 years of conventional therapy.

CONCLUSION

A total of 6.7% of PH patients had nephrocalcinosis, and 14% showed renal dysfunction. Prevalence of renal calculi was similar in patients and controls. Nine percent of patients developed nephrocalcinosis over 10 years of conventional therapy.