Endocrine Abstracts

Background/aim: Primary hyperparathyroidism (pHPT) is a relatively common endocrine disorder, which is often asymptomatic and thus diagnosed during routine biochemical testing. Emerging scientific data supports the theory that non-syndromic pHPT patients may be at increased risk for thyroid autoimmunity, metabolic disorders and malignancy.

Materials and methods: A cohort of 227 pHPT (61 male and 166 female) and 244 non-pHPT (75 male and 169 female) patients from our endocrinology outpatient clinics was included in the retrospective study. Demographic, clinical and laboratory data of these patients were evaluated retrospectively.

Results: Mean age and body mass index of pHPT and non-pHPT patients were comparable (60.3 vs 58.1 years, P=0.21 and 28 vs 27.1 kg/m², P=0.58). pHPT affected more often female patients (166/227-73%) Autoimmune thyroid disease (AITD) was more prevalent among pHPT patients (78/227 [34.4%] vs 26/244 [10.6%], P=0.01). pHPT patients had more often diabetes mellitus (DM) (46/227 [20.3%] vs 23/244 [9.4%], P=0.026). On the contrary, obesity (P=0.24) and impaired fasting glucose (IFG) (P=0.36) were equally observed among the groups. The overall occurrence of cancer was increased among the pHPT patients (59/227 [26%] vs 38/244 [15.5%], P<0.01). The most commonly observed malignancy among all patients was differentiated thyroid cancer, which was more prevalent among the pHPT patients (19/227 [8.4%] vs 12/244 [4.9%], P=0.014). Regarding other malignancies, pHPT patients exhibited higher malignancy rates (40/227 [17.6%] vs 26/244 [10.6%], P<0.01). Among the pHPT patients, breast cancer was more frequent (12/227 patients), followed by lung and uterus cancer (7/227 and 4/227 patients respectively). Among non-pHPT patients, breast, lung and intestinal cancer were more prevalent (9/244, 5/244 and 3/244 patients, respectively). Finally, among pHPT patients, female patients suffered more often from AITD (65/166 [39.1%] vs 13/61 [21.3%], P<0.01) and DM (36/166 [21.7%] vs 10/61 [16.4%], P=0.02). Additionally, women were more obese (84/166 [50.6%] vs 11/61 [18%], P=0.01) and had more often IFG (8/166 [4.8%] vs 2/61 [3.3%]. P=0.04) than men. Interestingly, the prevalence of cancer was equal among male and female pHPT patients (16/61 [26.2%] vs 43/166 [25.8%], P= 0.15).

Conclusions: Non-syndromic pHPT may be associated with increased risk for concomitant thyroid autoimmunity, metabolic disorders and malignancies. Thus, clinicians should be alert and routinely evaluate these patients for the previous mentioned pathological entities.