Does Bariatric Surgery Increase the Formation of Parathyroid Adenoma

Hypocalcemia after parathyroidectomy in patients with a history of bariatric surgery

PURPOSE

A growing body of literature has suggested that a history of bariatric surgery increases the risk of hypocalcemia after subsequent thyroidectomy, however little is known about the risk after parathyroidectomy. The purpose of this study was to determine the incidence of hypocalcemia after parathyroidectomy in patients with prior bariatric surgery.

METHODS

The TriNetX Research Network was queried using diagnosis and procedure codes to identify patients with a history of bariatric surgery who were subsequently diagnosed with primary hyperparathyroidism (PHP) and underwent parathyroidectomy between 2012 and 2022. The rate of hypocalcemia after parathyroidectomy was compared between those with a history of bariatric surgery and controls who underwent parathyroidectomy alone, matched for demographics, body mass index (BMI) ≥ 30 kg/m², and history of calcium or vitamin D supplementation.

RESULTS

There were 34,483 included patients diagnosed with PHP who underwent parathyroidectomy. Of this cohort, 1.4% (n = 472) had prior bariatric surgery. There were 90% females and 10% males in this subset of patients, and the average age was 58 years. Compared to matched controls who underwent parathyroidectomy alone, these patients had a significantly increased risk of hypocalcemia within 0-1 month (RR, 95% CI, P) (17.2% vs. 9.3%; 1.8, 1.3-2.6, P < 0.001), 1-6 months (8.5% vs. 2.5%; 3.3, 1.8-6.3, P < 0.001) and 6-12 months (6.8% vs. 2.3%; 2.9, 1.5-5.7, P < 0.001) following surgery.

CONCLUSION

The current study is the first to indicate that patients with a history of bariatric surgery are at increased risk for short-term and permanent hypocalcemia after parathyroidectomy. Further research is required to determine optimal prevention and treatment strategies to decrease associated morbidity in this subset of patients.

The Eucalcemic Patient With Elevated Parathyroid Hormone Levels

Primary hyperparathyroidism (PHPT) is classically characterized by hypercalcemia with elevated or inappropriately normal parathyroid hormone (PTH) levels. Elevated PTH levels in the presence of normal calcium levels are not infrequently found during the evaluation of metabolic bone disorders or kidney stone disease. This can be caused by secondary hyperparathyroidism (SHPT) or normocalcemic primary hyperparathyroidism (NPHPT). NPHPT is due to autonomous parathyroid function whereas SHPT is caused by a physiologic stimulation to PTH secretion. Many medical conditions and medications can contribute to SHPT, and differentiation between SHPT and NPHPT may be difficult. Cases are presented to illustrate examples. In this paper, we review the distinction between SHPT and NPHPT as well as end organ effects of NPHPT and outcomes of surgery in NPHPT. We suggest that the diagnosis of NPHPT be made only after careful exclusion of causes of SHPT and consideration of medications that can increase PTH secretion. Further, we advise a conservative approach to surgery in NPHPT.

Bone Response to Weight Loss Following Bariatric Surgery

Obesity is a global health challenge that warrants effective treatments to avoid its multiple comorbidities. Bariatric surgery, a cornerstone treatment to control bodyweight excess and relieve the health-related burdens of obesity, can promote accelerated bone loss and affect skeletal strength, particularly after malabsorptive and mixed surgical procedures, and probably after restrictive surgeries. The increase in bone resorption markers occurs early and persist for up to 12 months or longer after bariatric surgery, while bone formation markers increase but to a lesser extent, suggesting a potential uncoupling process between resorption and formation. The skeletal response to bariatric surgery, as investigated by dual-energy X-ray absorptiometry (DXA), has shown significant loss in bone mineral density (BMD) at the hip with less consistent results for the lumbar spine. Supporting DXA studies, analyses by high-resolution peripheral quantitative computed tomography (HR-pQCT) showed lower cortical density and thickness, higher cortical porosity, and lower trabecular density and number for up to 5 years after bariatric surgery. These alterations translate into an increased risk of fall injury, which contributes to increase the fracture risk in patients who have been subjected to bariatric surgery procedures. As bone deterioration continues for years following bariatric surgery, the fracture risk does not seem to be dependent on acute weight loss but, rather, is a chronic condition with an increasing impact over time. Among the post-bariatric surgery mechanisms that have been claimed to act globally on bone health, there is evidence that micro- and macro-nutrient malabsorptive factors, mechanical unloading and changes in molecules partaking in the crosstalk between adipose tissue, bone and muscle may play a determining role. Given these circumstances, it is conceivable that bone health should be adequately investigated in candidates to bariatric surgery through bone-specific work-up and dedicated postsurgical follow-up. Specific protocols of nutrients supplementation, motor activity, structured rehabilitative programs and, when needed, targeted therapeutic strategies should be deemed as an integral part of post-bariatric surgery clinical support.