Early Postoperative Parathormone and Calcium as Prognostic Factors for Postoperative Hypocalcemia

The predictive value of postoperative intact parathyroid hormone for symptomatic hypocalcemia in older patients with thyroid cancer

Background

Due to the unique characteristics of older patients, they are more susceptible to develop symptomatic hypocalcemia (SH). This study aimed to analyze the potential relationship between the occurrence of SH and various indicators in older patients after thyroid cancer surgery, and to further discuss the predictive value of postoperative intact parathyroid hormone (iPTH) for SH, which can provide reference for clinical prevention and treatment of hypocalcemia in older patients.

Methods

A total of 137 older patients with thyroid cancer (≥60 years old) admitted to the Department of Thyroid Surgery, Nanjing Drum Tower Hospital, The Affiliated Hospital of Nanjing University Medical School from January 2020 to December 2022 were selected. They were divided into the SH group and the asymptomatic group according to whether they developed SH. Relevant clinical data were collected and retrospectively analyzed. The measurement data of normal distribution were expressed by mean ± standard deviation (SD). Univariate and multivariate analyses were used to determine the risk factors for SH in older patients after thyroid cancer surgery. Statistical significance was set as P<0.05. Receiver operating characteristic (ROC) curve was constructed to study the predictive value of postoperative iPTH for SH occurrence in older patients with thyroid cancer.

Results

Among 137 older patients, 48 cases (35.04%) developed SH and 89 cases (64.96%) were asymptomatic. There were significant differences in preoperative iPTH (SH group: 7.00±5.25 pmol/L; asymptomatic group: 5.52±1.80 pmol/L; P=0.004) and postoperative iPTH (SH group: 0.69±0.95 pmol/L; asymptomatic group: 3.30±2.28 pmol/L; P<0.001) between the SH group and the asymptomatic group, with statistical significance (P<0.05). The area under the curve (AUC) of postoperative iPTH predicting SH occurrence in older patients with thyroid cancer was 0.855, cut-off was 0.5941 [95% confidence interval (CI): 0.794-0.917; sensitivity, 87.5%; specificity, 71.9%].

Conclusions

Postoperative iPTH is an independent risk factor for predicting SH in older patients with thyroid cancer. In order to avoid the occurrence of postoperative SH and reduce hospitalization costs and length, calcium supplementation should be given as soon as possible according to the level of postoperative iPTH.

A prospective cross-sectional study on hypocalcemia after total thyroidectomy in patients with Graves' disease: insights on secondary hyperparathyroidism

PURPOSE

To investigate the parathyroid function and calcium (Ca) levels in the secondary hyperparathyroidism (SHPT) state in patients with Graves' disease.

METHODS

We examined 31 consecutive patients with Graves' disease without chronic kidney disease, who were treated with total thyroidectomy. The patients were divided into a normal parathyroid hormone (PTH) group (NPTH group; n = 19) with a PTH level ≤ 65 pg/mL, and a secondary hyperparathyroidism group (SHPT group; n = 12), with a PTH level > 65 pg/mL. The PTH and Ca-related parameters were examined and the risk factors for postoperative hypocalcemia were analyzed.

RESULTS

The preoperative Ca level was significantly lower (2.24 ± 0.06 vs. 2.31 ± 0.07 mmol/L, p < 0.05) in the SHPT group than in the NPTH group. The reduction in PTH, 1,25-dihydroxyvitamin D (1,25(OH)2D), and Ca levels from the preoperative day to the next morning was significantly greater in the SHPT group than in the NPTH group (p < 0.05). When intraoperative factors were included, the decrease in the PTH level alone was significant. SHPT was a significant factor in determining the extent of PTH reduction.

CONCLUSIONS

Hyperfunctioning parathyroid glands in the SHPT state were more susceptible to postoperative PTH reduction, which, combined with low preoperative Ca levels, increased the risk of postoperative hypocalcemia in patients with Graves' disease.

Correction: Daskalaki et al. Early Postoperative Parathormone and Calcium as Prognostic Factors for Postoperative Hypocalcemia. J. Clin. Med. 2022, 11, 2389

In the published article [...].

Construction and validation of a predictive model for hypocalcemia after parathyroidectomy in patients with secondary hyperparathyroidism

OBJECTIVE

We aimed to construct and validate a predictive model for the risk of hypocalcemia following parathyroidectomy (PTX) for the treatment of secondary(renal) hyperparathyroidism (SHPT).

METHODS

Information regarding patients with SHPT who underwent PTX between January 2019 and April 2022 was collected retrospectively. Univariate and multivariate logistic regression analyses were used to identify independent risk factors for hypocalcemia following PTX and to construct predictive models. The areas under the receiver operating characteristic curve (AUC), the calibration curve, and the clinical decision curve (decision curve analysis, DCA) were used to assess the discrimination, calibration, and level of clinical benefit obtained using the predictive models.

RESULTS

We studied 238 patients who were randomly allocated in a 7:3 ratio to a training group (n=166) and a test group (n=72). Univariate and multivariate logistic regression analyses were performed, in which three variables (the circulating parathyroid hormone (PTH) and Ca concentrations, and alkaline phosphatase (ALP) activity) were interrogated for possible roles as independent risk factors for hypocalcemia in patients with SHPT who undergo PTX, and used to construct predictive models. The AUCs for the constructed models were high for both the training (0.903) and test (0.948) groups. The calibration curve showed good agreement between the incidence of postoperative hypocalcemia estimated using the predictive model and the actual incidence. The DCA curve indicated that the predictive model performed well.

CONCLUSION

A predictive model constructed using a combination of preoperative PTH, Ca, and ALP may represent a useful means of identifying patients with SHPT at high risk of developing hypocalcemia following PTX in clinical practice.