Eucalcemic Parathyroid Hormone Elevation After Parathyroidectomy for Primary Sporadic Hyperparathyroidism: Risk Factors, Trend, and Outcome

Abstract

BackgroundPatients with eucalcemic parathyroid hormone elevation (ePTH) after parathyroidectomy for primary hyperparathyroidism (HPT) may be at risk of recurrence. We aimed to examine risk factors, trend of PTH level, and outcome of patients with ePTH 6 months after parathyroidectomy.MethodsA total of 161 primary HPT were analyzed. The 6-month postoperative calcium and PTH levels were obtained. ePTH was defined as an elevated PTH level in the presence of normocalcemia. At 6 months, 98 had eucalcemic normal PTH and 63 (39.1%) had ePTH. Perioperative variables, PTH trend, and outcome were compared between 2 groups. Multivariable analyses were performed to identify independent preoperative and operative/postoperative risk factors for ePTH.ResultsAmong preoperative factors, advanced age (odds ratio [OR] = 1.042, P = .027) and low 25-hydroxyvitamin D3 (25OHD3) (OR = 1.043, P = .009) were independently associated with ePTH, whereas among operative/postoperative factors, high 10-min intraoperative PTH level (OR = 1.015, P = .040) and high postoperative 3-month PTH (OR = 1.048, P < .001) were independently associated with ePTH. After a mean follow-up of 38.7 months, recurrence rate was similar between the 2 groups (P = 1.00). In the first 2 postoperative years, 75 (46.6%) had ePTH on at least 1 occasion and 8 (5.0%) had persistently ePTH on every occasion.ConclusionsAdvanced age, low 25OHD3, high 10-min intraoperative PTH, and high postoperative 3-month PTH were independently associated with ePTH at 6-month. Although 39.1% of patients had ePTH at 6 months, more than 50% had at least 1 ePTH within the first 2 years of follow-up. Recurrence appeared similar between those with or without ePTH at 6 months.

Elevated parathyroid hormone after parathyroidectomy delays symptom improvement

“…High pre-operative and early post-operative levels of PTH have consistently been shown to correlate with ePTH 2,13–15,18,19,21 , and we confirmed this relationship as well. A subset of studies have also found advanced age to be a predictor 20,21 , as was seen in our data. Prior research has shown that ePTH patients have lower pre-operative D-25-OH levels 13,17,20 , and though our univariate analysis showed the same trend, it was not statistically significant.…”

“…A subset of studies have also found advanced age to be a predictor 20,21 , as was seen in our data. Prior research has shown that ePTH patients have lower pre-operative D-25-OH levels 13,17,20 , and though our univariate analysis showed the same trend, it was not statistically significant. Furthermore, in this study, patients classified as having inadequate vitamin D were no more likely to have ePTH at either 2 weeks or 6 months.…”

“…This finding raises the possibility that patients with short term and longer term ePTH may have different etiologies. Other authors have found considerable fluctuations in patients’ PTH elevation over time as well, though the significance of this phenomenon still remains unclear 14,15,16,20 . Nordenstrom et al examined ePTH with a follow-up of 5 years and categorized patients into “Normal”, “Normalized”, and “Variable” groups based on the stability of their ePTH levels over time, and found significant differences in biochemistry between the groups 15 .…”

Significance of Rebounding Parathyroid Hormone Levels During Parathyroidectomy

“…The incidence of this phenomenon ranges from 12 to 43% of cases (19), and these patients tend to be older, deficient in Vitamin D, and have biochemical markers of more severe hyperparathyroidism (20)(21)(22)(23)(24). Similar to this study, our group has previously shown that recurrence is higher in the subset of patients who display elevations in PTH postoperatively (24).…”

Comment on: Eucalcemic Parathyroid Hormone Elevation After Parathyroidectomy for Primary Sporadic Hyperparathyroidism: Risk Factors, Trend, and Outcome

“…We read the article ''Eucalcemic parathyroid hormone elevation after parathyroidectomy for primary sporadic hyperparathyroidism: risk factors, trend, and outcome'' by Lang et al 1 with interest. The authors have addressed a very valid and important scenario after parathyroidectomy.…”