The purpose of this study is to assess glycemic control after parathyroidectomy in patients with primary hyperparathyroidism and concomitant type 2 diabetes mellitus.

Primary hyperparathyroidism (PHPT) is known to affect the kidney and skeletal system, however, recent data have suggested that patients can also exhibit an increased cardiovascular risk and metabolic abnormalities Primary hyperparathyroidism (PHPT) is the most common cause of hypercalcemia, with an estimated prevalence of 0.8% in the general population. Type 2 diabetes mellitus (DM) is the most prevalent chronic disease with an estimated prevalence of 10%. Based on the estimated prevalence of this two conditions, we would expect a comorbid prevalence of both diseases in the same individual of approximately 0.08%. However, the prevalence of DM in patients with PHPT is much higher ranging from anywhere 7.8% to 22%, suggesting that this is not mere coincidence.

While the exact mechanism is not clear, in vivo study demonstrated that parathyroid hormone (PTH) reduces the insulin-stimulated uptake as well as decrease glucose transporter and the insulin receptor. Hypercalcemia can also be associated with impaired insulin sensitivity and insufficient suppression of gluconeogenesis. In some patient series, some improvement in glycemic profiles have been shown in patients after parathyroidectomy (PTX).

In addition, both DM and PHPT are known risk factors for the development of bone abnormality patients with DM have increased risk of hip fractures while cortical bone (i.e. the forearm) are more commonly affected in patients with PHPT. There are currently very few studies evaluating the interaction of both conditions in terms of patient skeletal profiles and bone health.

Participants with PHPT and DM will be recruited and followed over the course of a year. There are two groups: the group of patients that decided to pursue a parathyroidectomy, and a group of patients that will be managed non-surgically. Clinical data will be collected along with blood tests.

Inclusion Criteria:

1. Study group: Consecutive patients older than 18 years old with concomitant PHPT and DM who will undergo PTX. The indications and need for surgery will be independent from the research team.
2. Control group: Consecutive patients older than 18 years old with concomitant PHPT and DM who will not undergo PTX. The indications to forgo surgery will be independent from the research team.

Exclusion Criteria:

1. Patients with recurrent or persistent PHPT will not be included.
2. Patients who are included but have evidence of recurrent or persistent PHPT based on six-month laboratory workup will be excluded from the final analysis (<5% expected)9.
3. Patients with type 1 diabetes mellitus
4. Patients with secondary and/or tertiary hyperparathyroidism

Participants will be recruited from a multi-specialty academic medical center coming in to see their physician for surgery, and/or management of their PHPT and DM.