Does Obesity Affect the Clinical Course and Accompanying Metabolic Disorders in Primary Hyperparathyroidism?

Several studies suggest an increased prevalence of obesity among patients with primary hyperparathyroidism (PHPT). Proposed mechanisms include parathyroid hormone (PTH) resistance, resistance to adipokines, and reduced lipolysis. Obesity may influence the clinical severity and presentation of PHPT. In addition to obesity, metabolic disorders such as diabetes mellitus and hypertension are also frequently observed in PHPT; however, the specific contribution of obesity to these comorbidities remains unclear. This study aimed to determine the prevalence of obesity in PHPT and to investigate its association with clinical presentation, laboratory parameters, and comorbid conditions. We retrospectively analyzed data from 152 patients with surgically confirmed PHPT. Patient records were reviewed for body mass index (BMI), laboratory values, coexisting metabolic conditions, and PHPT-related complications such as nephrolithiasis, osteoporosis, and fracture history. Among the patients, 20.4% had prediabetes, 13.8% had diabetes, and 34.9% had hypertension. Obesity (BMI ≥ 30 kg/m²) was present in 27%, and 36.8% were overweight. Thyroid nodules were found in 50.7%, and anti–thyroid peroxidase (anti-TPO) positivity was detected in 16.4%. Serum calcium and PTH levels were significantly higher in obese patients compared to those with normal BMI (p ≤ 0.001 and p = 0.017, respectively). There was no significant difference in the incidence of fractures, osteoporosis, or nephrolithiasis between the obese and nonobese groups. While diabetes was more prevalent in the nonobese group overall, subgroup analysis revealed a higher frequency of diabetes in overweight and obese patients compared to those with normal BMI. The prevalence of obesity in PHPT was higher than that in the general population. Although obesity was not associated with an increased frequency of osteoporosis, nephrolithiasis, or fractures, elevated serum calcium and PTH levels in obese patients may suggest a relationship with disease severity.