Preoperative Vitamin D Deficiency is a Risk Factor for Postthyroidectomy Hypoparathyroidism: A Systematic Review and Meta-Analysis of Observational Studies

Impact of oral administration of calcitriol to prevent symptomatic hypocalcemia after total thyroidectomy: Systematic review and meta-analysis

BACKGROUND

One of the most common complications of total thyroidectomy is post-operative transient or persistent hypoparathyroidism that can cause symptomatic hypocalcaemia. To prevent this complication, shorten the period of hospitalization and reduce morbidity, routine supplementation of oral vitamin D and calcium has been suggested. This systematic review and meta-analysis aims to critically assess the association between pre-operative calcitriol supplementation and post-operative hypocalcaemia.

METHODS

Randomized controlled trial studies were identified by searching PubMed, Scopus, and Google Scholar databases up to 30 March 2023. Screening of titles, abstracts, and full texts of articles were performed, and data were extracted for a meta-analysis.

RESULTS

This meta-analysis includes data from nine randomized controlled trials with a total of 1259 patients but with significant heterogeneity. The results demonstrate that calcium levels were higher in patients who had pre-operative calcitriol supplementation, with a weighted mean difference (WMD) 0.18 (95% confidence interval (CI) = 0.00, 0.37). Pre-operative calcitriol supplementation did not lead to significant changes in parathyroid hormone (PTH) levels, with WMD -0.49 (95% CI: -1.91, 0.94).

CONCLUSION

Pre-operative calcitriol supplementation leads to higher calcium levels, but the high heterogeneity of the included studies (79% to 98.7%) could affect the results.

Does Vitamin D Deficiency Really Increase the Risk of Post-surgical Hypoparathyroidism?

Purpose

Postoperative hypoparathyroidism is the most frequent complication after total thyroidectomy. The identification of preoperative predictors could be helpful to identify patients at risk. The aim of this study is to determine if preoperative vitamin D levels are related to transient, protracted, and permanent hypoparathyroidism.

Method

A prospective, observational study that includes 100 patients who underwent total thyroidectomy.

Results

Transient hypoparathyroidism was present in 42% of patients, 11% developed protracted hypoparathyroidism and 5% permanent hypoparathyroidism. The median preoperative Vitamin D levels were higher in patients who developed transient hypoparathyroidism than in patients without this complication (24 ng/mL [RIQ 13-31] vs. 17 ng/mL [RIQ 10-24]; p = 0.024). Patients with preoperative vitamin D levels below 20 ng/mL had a lower percentage of transient hypoparathyroidism (31.4% vs. 53.1%; p = 0.028). The prevalence of protracted and permanent hypoparathyroidism in both groups was similar. Patients with preoperative vitamin D levels lower than 20 pg/mL had higher median PTH levels 24 h after surgery, (37.7 ± 28.2 pg/ml vs. 23.6 ± 18.6 pg/ml; p = 0.037), and suffered a lower postoperative PTH decline (46.2 ± 35.4% vs. 61 ± 29%; p = 0.026).

Conclusions

Patients with vitamin D deficiency had a lower transient hypoparathyroidism rate, higher median PTH levels 24 h after surgery and a lower postoperative PTH decline. We found no association between preoperative vitamin D and the development of protracted or permanent hypoparathyroidism.

Effect of near infrared autofluorescence guided total thyroidectomy on postoperative hypoparathyroidism: a randomized clinical trial

PURPOSE

The purpose of this single-blinded, 2-centre, randomized controlled trial was to test if near-infrared (NIR) autofluorescence image guidance for parathyroid gland (PG) detection during total thyroidectomy can reduce the incidence of hypoparathyroidism in both malignant and benign cases.

METHOD

Patients admitted for primary or completion total thyroidectomy were randomized to either the NIR intervention group or the standard care NONIR (no near infrared) group. The primary endpoint was the rate of hypoparathyroidism at the 3-month follow-up, defined as hypocalcemia and inappropriately low parathyroid hormone levels and/or continuous treatment with active vitamin D. The secondary endpoint was the PG identification rate.

RESULTS

A total of 147 patients were included of whom 73 were allocated to NIR. Primary or completion thyroidectomy was conducted in 84 and 63 cases, respectively. A total of 130 completed 3 months follow-up. Postoperative hypoparathyroidism in the NIR group at 12 h, 1 month and 3 months was, respectively, 31.8, 14.1, 6.5% compared with 35.9, 18.9, 11.8% in the NONIR group (all p > 0.46). In the NIR group, the identification rate of PGs was 69.5% (146 of 210 PGs), and 9% (19 of 210 PGs) were identified only due to additional use of NIR. For 15 out of 69 patients (21.7%) additionally PGs was found.

CONCLUSION

Hypoparathyroidism was nominally less frequent in the NIR group, although not statistically significant. Further studies are needed to confirm if NIR may be a supportive PG identification tool to minimize the number of PG which would have been otherwise missed, especially during more complicated thyroid procedures.

TRIAL REGISTRY

ClinicalTrials.gov: NCT04193332. Registration date: 16.08.2019.

Vitamin D: sources, physiological role, biokinetics, deficiency, therapeutic use, toxicity, and overview of analytical methods for detection of vitamin D and its metabolites

Vitamin D has a well-known role in the calcium homeostasis associated with the maintenance of healthy bones. It increases the efficiency of the intestinal absorption of dietary calcium, reduces calcium losses in urine, and mobilizes calcium stored in the skeleton. However, vitamin D receptors are present ubiquitously in the human body and indeed, vitamin D has a plethora of non-calcemic functions. In contrast to most vitamins, sufficient vitamin D can be synthesized in human skin. However, its production can be markedly decreased due to factors such as clothing, sunscreens, intentional avoidance of the direct sunlight, or the high latitude of the residence. Indeed, more than one billion people worldwide are vitamin D deficient, and the deficiency is frequently undiagnosed. The chronic deficiency is not only associated with rickets/osteomalacia/osteoporosis but it is also linked to a higher risk of hypertension, type 1 diabetes, multiple sclerosis, or cancer. Supplementation of vitamin D may be hence beneficial, but the intake of vitamin D should be under the supervision of health professionals because overdosing leads to intoxication with severe health consequences. For monitoring vitamin D, several analytical methods are employed, and their advantages and disadvantages are discussed in detail in this review.

Etiology and Pathophysiology of Hypoparathyroidism: A Narrative Review

The approach utilized a systematic review of the medical literature executed with specifically designed criteria that focused on the etiologies and pathogenesis of hypoparathyroidism. Enhanced attention by endocrine surgeons to new knowledge about parathyroid gland viability are reviewed along with the role of intraoperative parathyroid hormone (ioPTH) monitoring during and after neck surgery. Nonsurgical etiologies account for a significant proportion of cases of hypoparathyroidism (~25%), and among them, genetic etiologies are key. Given the pervasive nature of PTH deficiency across multiple organ systems, a detailed review of the skeletal, renal, neuromuscular, and ocular complications is provided. The burden of illness on affected patients and their caregivers contributes to reduced quality of life and social costs for this chronic endocrinopathy. © 2022 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).

How Long Does It Take to Regain Normocalcaemia in the Event of Postsurgical Hypoparathyroidism? A Detailed Time Course Analysis

Background: Postsurgical hypoparathyroidism (PH) is the most common side effect of bilateral thyroid resections. Data regarding the time course of recovery from PH are currently unavailable. Therefore, a detailed analysis of the time course of PH recovery and conditions associated with rapid recovery was conducted. Methods: This is a retrospective analysis of prospectively documented data. Patients with biochemical signs of PH or need for calcium supplementation were followed-up for 12 months. Logistic regression analyses were used to identify covariates of early as opposed to late recovery from PH. Results: There were 1097 thyroid resections performed from 06/2015 to 07/2016 with n = 143 PH. Median recovery time was 8 weeks and six patients (1.1% of total thyroid resections) required calcium supplementation > 12 months. Recovery of PH within 4 and 12 weeks was characterized by high PTH levels on the first postoperative day (4 weeks: OR 1.13, 95% CI 1.06−1.20; 12 weeks: OR 1.08, 95%CI 1.01−1.16). Visualization of all PTGs emerged as an independent predictor of recovery within 12 months (OR 2.32, 95% CI 1.01−4.93) and 24 weeks (OR 2.69, 95% CI 1.08−6.69). Conclusion: In the setting of specialized high-volume endocrine surgery, permanent PH is rare. However, every second patient will require more than 2 months of continued medical surveillance. Early recovery was associated with only moderately decreased postsurgical PTH-levels. Successful late recovery appeared to be associated with the number of parathyroid glands visualized during surgery.

Vitamin D Insufficiency Predicts Susceptibility of Parathyroid Hormone Reduction after Total Thyroidectomy in Thyroid Cancer Patients

OBJECTIVE

Given its role in the regulation of calcium and PTH levels, vitamin D was presumed as a potential predictor of postoperative hypoparathyroidism. However, the reports about their association were controversial. This study aims to reveal the relationship between preoperative vitamin D and postoperative parathyroid hormone (PTH).

METHODS

A total of 242 papillary thyroid cancer (PTC) patients who underwent total thyroidectomy (TT) during the period from June 2016 to December 2017 at our hospital were enrolled. Patients were divided into two groups, HypoP and Non-HypoP groups, based on postoperative PTH < 15.0 or ≥15.0 pg/mL, and ΔPTH₅₀+ and ΔPTH₅₀- groups, based on postoperative PTH reduction ratio ≥ 50% or <50%. Clinicopathological features and laboratory data were compared between two sets of groups.

RESULTS

Preoperative PTH level was lower in the HypoP group than in the Non-HypoP group (42.83 vs. 47.52 pg/mL, p=0.018). No significant difference of vitamin D insufficiency was found between the HypoP and Non-HypoP groups (80.8% vs. 74.1%, p=0.226). The rate of vitamin D insufficiency was higher in the ΔPTH₅₀+ group than in the ΔPTH₅₀- group (82.6% vs. 68.4%, p=0.010). By multivariate logistic regression analysis, vitamin D insufficiency was an independent predictor of postoperative PTH reduction ratio ≥ 50% (OR = 2.2, p=0.017).

CONCLUSION

Vitamin D insufficiency is not associated with postoperative PTH in PTC patients undergoing TT. However, vitamin D insufficiency is an independent predictor of postoperative PTH reduction ratio.