The relationship between postoperative parathormone suppression and surgical cure in primary hyperparathyroidism

In primary hyperparathyroidism(pHPT), suppression in other glands due to autonomy of pathological gland is frequently observed. In this retrospective study, we aimed to evaluate contribution of suppression of remaining parathyroid glands in pHPT in predicting surgical cure.

We retrospectively analyzed data from patients diagnosed with pHPT and operated at our institution between 2014 and 2022. Patients who demonstrated either a decrease of more than 50% in intraoperative parathormone levels or a normal parathormone (PTH) level at the 6th postoperative hour were included. Patients were categorized into two groups based on their PTH levels at the 6th postoperative hour: those with PTH suppression (PTH < 15 ng/L) and those without (PTH > 15 ng/L). We analyzed the outcomes in terms of persistent disease and biochemical markers.

Among 196 patients who met the inclusion criteria, 124 exhibited PTH suppression while 72 did not. Persistent disease was significantly more common in the non-suppressed group (19.4% vs. 5.65%, p<0.001). Furthermore, postoperative PTH suppression strongly correlated with surgical cure, indicated by a significant difference in the rate of normocalcemia after 6 months. Excised parathyroid tissue volumes were determined significantly lower in group 1 compared to group (0.85 ± 0.88cm3vs2.04 ± 3.79cm3,p=0.035, respectively).There was no significant difference between two groups in terms of gender, preoperative Ca, magnesium, vitamin D and postoperative Ca levels.

Early postoperative PTH suppression is highly associated with surgical cure. The rate of pPHPT is significantly higher in non-suppressed patients. Therefore, in follow-up strategies of postoperative patients, the possibility of a remnant pathological gland should be considered especially in those without early PTH suppression.