Risk factors of transient and permanent hypoparathyroidism after thyroidectomy: a systematic review and meta-analysis

Abstract

Background: Postoperative hypoparathyroidism (hypoPT) is a common complication following thyroid surgery. However, current research findings on the risk factors for post-thyroid surgery hypoPT are not entirely consistent, and the same risk factors may have different impacts on transient and permanent hypoPT. Therefore, there is a need for a comprehensive study to summarize and explore the risk factors for both transient and permanent hypoPT after thyroid surgery.

Materials and methods: Two databases (PubMed and Embase) were searched from inception to 2024. The Newcastle-Ottawa Scale was used to rate study quality. Pooled odds ratios were used to calculate the relationship of each risk factor with transient and permanent hypoPT. Subgroup analyses were conducted for hypoPT with different definition-time (6 or 12 months). Publication bias was assessed using Begg's test and Egger's test.

Results: A total of 19 risk factors from the 93 studies were included in the analysis. Among them, sex and parathyroid autotransplantation were the most frequently reported risk factors. Meta-analysis demonstrated that sex (female vs. male), cN stage, central neck dissection, lateral neck dissection, extent of central neck dissection (bilateral vs. unilateral), surgery [total thyroidectomy (TT) vs. lobectomy], surgery type (TT vs. sub-TT), incidental parathyroidectomy, and pathology (cancer vs. benign) were significantly associated with transient and permanent hypoPT. Preoperative calcium and parathyroid autotransplantation were only identified as risk factors for transient hypoPT, while preoperative PTH was a protective factor. Additionally, node metastasis and parathyroid in specimen were associated with permanent hypoPT.

Conclusion: The highest risk of hypoPT occurs in female thyroid cancer patients with lymph node metastasis undergoing TT combined with neck dissection. The key to preventing postoperative hypoPT lies in the selection of surgical approach and intraoperative protection.

Figure 1

PRISMA diagram showing screening and selection of studies for systematic review and meta-analysis. hypoPT, hypoparathyroidism.

Figure 2

Distribution and results of studies considered for systematic review and meta-analysis. (A) Distribution of results from univariable analysis in included studies for transient hypoPT. (B) Distribution of results from multivariate analysis in included studies for transient hypoPT. (C) Distribution of results from univariable analysis in included studies for permanent hypoPT. (D) Distribution of results from multivariate analysis in included studies for permanent hypoPT. cN, clinical N; CND, central neck dissection; LND, lateral neck dissection; PTH, parathyroid hormone; PGRIS, parathyroid glands remaining in situ; Transient hypoPT, Transient hypoparathyroidism; TT, total thyroidectomy; Permanent hypoPT, Permanent hypoparathyroidism.

Figure 3

Forest plots showing the meta-analysis results for each potential risk factor. This figure displays the combined results of meta-analysis for both transient and permanent hypoPT, with the specific inclusion details of each study shown in the supplementary figures. CND, central neck dissection; cN, clinical N; hypoPT, hypoparathyroidism; LND, lateral neck dissection; OR, odds ratio; PTH, parathyroid hormone; PGRIS, parathyroid glands remaining in situ; TT, total thyroidectomy.

Figure 4

Forest plots showing the subgroup meta-analysis results for each potential risk factor of transient hypoPT. This figure displays the results of subgroup meta-analysis for transient hypoPT with different definition time, and the specific inclusion details of each study were shown in the supplementary figures. cN, clinical N; CND, central neck dissection; hypoPT, hypoparathyroidism; LND, lateral neck dissection; OR, odds ratio; PTH, parathyroid hormone; PGRIS, parathyroid glands remaining in situ; TT, total thyroidectomy.

Figure 5

Forest plots showing the subgroup meta-analysis results for each potential risk factor of permanent hypoPT. This figure displays the results of subgroup meta-analysis for permanent hypoPT with different definition time, and the specific inclusion details of each study were shown in the supplementary figures. cN, clinical N; CND, central neck dissection; hypoPT, hypoparathyroidism; LND, lateral neck dissection; OR, odds ratio; PTH, parathyroid hormone; PGRIS, parathyroid glands remaining in situ; TT, total thyroidectomy.