Endocrine Abstracts

Introduction

The incidence of primary hyperparathyroidism (PHPT) increases with age; however, the clinical presentation might change with aging. We aimed to compare the clinical presentation of older and younger patients with PHPT.

Methods

We retrospectively analyzed the biochemical status, renal involvement, and bone mineral density (BMD) of patients who were diagnosed with PHPT at our endocrine clinic from 2004 to 2016. Patients over 65 years of age were compared to younger patients.

Results

We included 426 adult patients (339 women and 87 men) with PHPT. There were 231 patients over 65 years with a mean age of 73.4 (SD 5.3) years and 195 younger patients with a mean age of 52.2 (10.0) years. Gender distribution was similar with 49 (21.2%) males in older group and 38 (19.5%) males in younger group (P = 0.66). Older patients had biochemically less florid disease at presentation with a lower mean serum calcium: 2.72 (0.25) mmol/l vs. 2.79 (0.29) mmol/l; P = 0.01, lower urinary calcium: 5.18 (4.0) mmol vs. 8.39 (4.6) mmol; P < 0.01 and higher phosphate: 0.84 (0.15) mmol/l vs.0.8 (0.18) mmol/l; P = 0.02, but also higher creatinine: 83.56 (31.92) µmol/l vs. 72.23 (26.32) µmol/l; P < 0.01, lower estimated glomerular filtration rate: 68.4 (18.1) ml/min vs. 79.4 (14.5) ml/min; P < 0.01 and lower 25-OH vitamin D levels: 39.63 (22.41) nmol/l vs. 43.92 (21.53) nmol/l; P = 0.02. PTH and alkaline phosphatase levels did not differ between groups. Fewer older patients had nephrolithiasis and/or nephrocalcinosis than younger patients (56 out of 231 or 24.2% vs. 78 out of 195 or 40%; P < 0.01). BMD was significantly lower in older patients than in younger patients at the total hip (0.786 (0.157) g/cm² vs. 0.876 (0.150) g/cm²; P < 0.01), femoral neck (0.640 (0.113) g/cm² vs. 0.717 (0.125) g/cm²; P < 0.01) and at one-third distal radius (0.564 (0.108) g/cm² vs. 0.625 (0.100) g/cm²; P < 0.01). There were no differences in BMD at the lumbar spine. Finally, 139 out of 231 older patients (60.2%) were diagnosed with osteoporosis, which was found in only 71 out of 195 younger patients (36.4%; P < 0.01).

Conclusion

Based on our study, patients with PHPT who are older than 65 years present with biochemically less florid disease and less nephrolithiasis/nephrocalcinosis, but with more severe bone impairment than younger patients.