Ejlsmark-Svensson H, et al. - In patients with primary hyperparathyroidism (PHPT), researchers investigated the prevalence and possible biochemical predictive factors of renal calcifications. They found that patients with PHPT frequently developed renal calcifications which were associated with disease severity. In addition, patients with PHPT were commonly found to have impaired renal function, but renal function was not related to renal calcifications.

Methods

• Researchers performed this nested case-control study in a university hospital setting with 792 patients with PHPT from 2005 to 2015.
• They used biochemical data to validate the diagnosis of PHPT.
• The main outcome measures included the prevalence of renal calcifications defined as nephrolithiasis or nephrocalcinosis evaluated by a routine CT scan at the time of diagnosis.

Results

• Of 792 identified patients with PHPT, 617 patients (78%) had a CT scan.
• The estimated prevalence of renal calcifications was 23%, and was found to be equally frequent between sexes.
• Nephrolithiasis and nephrocalcinosis was seen in a total of 76 patients (12%) and 75 patients (12%), respectively, where 7 patients (1%) had both nephrolithiasis and nephrocalcinosis.
• Significantly higher levels of ionized calcium, parathyroid hormone, and 24-hour calcium excretion (P_all < 0.01) were observed among patients with renal calcifications vs those without renal calcifications.
• Findings revealed higher plasma levels of phosphate and a higher calcium-phosphate product among patients with nephrocalcinosis vs those with nephrolithiasis (Pall < 0.05).
• Twelve percent of patients had impaired renal function (estimated glomerular filtration rate <60 mL/min).
• Renal function did not differ between those with and without renal calcifications.