Primary Hyperparathyroidism Across the Age Spectrum: A Comparative Study of Clinical and Biochemical Profiles in Older and Younger Patients

hypercalcemia.Elevated PTH leads to hypercalcemia by increasing Ca reabsorption in the kidneys, enhancing bone resorption, and stimulating renal production of 1,25-dihydroxyvitamin D (25OHD), which promotes intestinal absorption of Ca and phosphate.Most cases are sporadic and are caused by a single AbstractObjective: Primary hyperparathyroidism (PHPT) is characterized by elevated serum calcium (Ca) levels due to excessive parathyroid hormone (PTH) secretion and is traditionally associated with skeletal and renal complications, such as osteoporosis and nephrolithiasis.With routine measurements of serum Ca, most cases are now diagnosed asymptomatically although subclinical complications like osteoporosis or hypercalciuria may still occur.This study investigated the impact of aging on the clinical and biochemical profiles of PHPT by comparing a large cohort of older and younger patients, thereby addressing the gap in understanding the disease's age-related characteristics. Materials and Methods:This retrospective study analyzed patients diagnosed with PHPT who underwent surgical treatment.Demographic data, including age and gender, along with biochemical parameters serum Ca, corrected calcium (cCa), phosphorus, albumin, PTH, 24-hours urinary Ca, estimated glomerular filtration rate (eGFR), fractional calcium excretion (FECa), and 25-hydroxyvitamin D (25OHD) were collected.Renal imaging and dual-energy X-ray absorptiometry were used to assess nephrolithiasis and osteoporosis, respectively.Patients were stratified into two groups: those younger than 60 (Group 1) and those aged 60 and older (Group 2).The groups were compared according to the prevalence of osteoporosis, nephrolithiasis, and biochemical parameters. Results:The cCa levels were significantly higher in Group 2, with a median of 11.1 mg/dL, compared with 10.8 mg/dL in Group 1 (p=0.002).The median serum 25OHD level was lower in Group 1 (13.2 ng/mL) than in Group 2 (17 ng/mL, p<0.001).Median 24-hours urinary Ca excretion was higher in Group 1 (375.5 mg) than in Group 2 (308 mg, p=0.003).FECa was similar between the groups, with a median of 0.02 in Group 1 and 0.02 in Group 2 (p=0.88).eGFR was significantly higher in Group 1 (median, 102 mL/min/1.73m 2 , compared to 84 mL/min/1.73m 2 in Group 2 (p<0.001).The prevalence of nephrolithiasis was similar between the groups, affecting 33.5% of patients in Group 1 and 31.8% in Group 2 (p=0.69).Osteoporosis was significantly more common in Group 2 (62.3% of patients) than in Group 1 (40% in Group 1 (p<0.001). Conclusion:Aging plays a pivotal role in the clinical presentation of PHPT, with distinct patterns emerging across different age groups.In particular, older adults exhibit a higher prevalence of osteoporosis.