Normocalcemic primary hyperparathyroidism: a survey in a small village of Southern Italy.

We investigated the prevalence of normocalcemic primary hyperparathyroidism (NPHPT) in the adult population living in a village in Southern Italy. All residents in 2010 (n=2045) were invited by calls and 1046 individuals accepted to participate. Medical history, calcium intake, calcium, albumin, creatinine, parathyroid hormone (PTH) and 25OHD were evaluated. NPHPT was defined by normal albumin-adjusted serum calcium, elevated plasma PTH, and exclusion of common causes of secondary hyperparathyroidism (SHPT) (serum 25OHD <30 ng/ml, estimated glomerular filtration rate (eGFR) <60 ml/min per 1.73 m(2) and thiazide diuretics use), overt gastrointestinal and metabolic bone diseases. Complete data were available for 685 of 1046 subjects. Twenty subjects did not meet the inclusion criteria and 341 could not be evaluated because of thawing of plasma samples. Classical PHPT was diagnosed in four women (0.58%). For diagnosing NPHPT the upper normal limit of PTH was established in the sample of the population (n=100) who had 25OHD ≥30 ng/ml and eGFR ≥60 ml/min per 1.73 m(2) and was set at the mean+3s.d. Three males (0.44%) met the diagnostic criteria of NPHPT. These subjects were younger and with lower BMI than those with classical PHPT. Our data suggest, in line with previous studies, that NPHPT might be a distinct clinical entity, being either an early phenotype of asymptomatic PHPT or a distinct variant of it. However, we cannot exclude that NPHPT might also represent an early phase of non-classical SHPT, since other variables, in addition to those currently taken into account for the diagnosis of NPHPT, might cumulate in a normocalcemic subject to increase PTH secretion.

Cinacalcet efficacy in patients with moderately severe primary hyperparathyroidism according to the European Medicine Agency prescription labeling.

BACKGROUND: Patients with primary hyperparathyroidism (PHPT) with contraindications to parathyroidectomy (PTx) or persistent PHPT have few non surgical options. AIM: The aim of the study was to investigate the efficacy of cinacalcet in reducing serum calcium in patients with PHPT, for whom PTx would be indicated according to serum calcium levels, but in whom PTx is not clinically appropriate or is contraindicated [European Medicines Agency (EMA) prescription labeling]. SUBJECTS AND METHODS: The study (open-label prospective, conducted in a single tertiary center) included 12 sporadic and 2 multiple endocrine neoplasia type 1 PHPT patients with serum calcium greater than 11.2 mg/dl. Cinacalcet was administered in increasing doses until normal serum calcium was reached or side effects preventing a further increase occurred. Serum calcium, PTH, phosphate, 25OHD, markers of bone turnover, 24h-urinary calcium and areal bone mineral density (BMD) were measured. Safety biochemical indices and adverse events were monitored. RESULTS: The maintenance cinacalcet dose [median 30 mg twice daily (range 30 daily-60 mg twice daily)] was maintained constant during follow-up (median 12 months). Mean±SE baseline serum calcium was 12.2±0.3 mg/dl. Serum calcium decreased by at least 1 mg/dl in all patients and normalized in 10. Serum calcium at the last observation was 9.9±0.2 mg/dl (p<0.0001 vs baseline). PTH decreased by 17.1% compared to baseline (p=0.13), and never reached a normal value. BMD was unchanged. Adverse events occurred in 6 patients (43%) and required treatment withdrawal in 2. CONCLUSIONS: Cinacalcet reduced and often normalized serum calcium in PHPT patients who met the EMA labeling.