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Trial registered on ANZCTR

Registration number
Ethics application status
Date submitted
Date registered
Date last updated
Type of registration
Prospectively registered

Titles & IDs
Public title
A Study to Compare Oral Vitamin D to Placebo for the Prevention of Low Calcium in the Blood after Surgery for the Total Removal of the Thyroid Gland.
Scientific title
A Randomised, Double Blind, Placebo Controlled Trial to Assess the Efficacy of Preoperative Oral Vitamin D3 at Preventing Postoperative Hypocalcaemia in Patients Undergoing Total Thyroidectomy.
Secondary ID [1] 284111 0
Universal Trial Number (UTN)
Trial acronym
Vitid Study
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Post-operative Hypocalcaemia 291189 0
Total Thyroidectomy 291190 0
Condition category
Condition code
Metabolic and Endocrine 291524 291524 0 0
Other metabolic disorders
Surgery 291525 291525 0 0
Other surgery

Study type
Description of intervention(s) / exposure
300 000 IU (6 capsules) of oral Vitamin D3 taken once, one week prior to surgery.
Intervention code [1] 288805 0
Treatment: Drugs
Comparator / control treatment
Placebo 6 capsules (sugar pills) taken once, one week prior to surgery.
Control group

Primary outcome [1] 291495 0
The incidence of low blood calcaemia (defined as any post-operative corrected calcium <2.10 mmol/L)
Timepoint [1] 291495 0
At 6 hours, days 1, 2, 3 (if still in hospital), 1 week, 2 weeks, 4 weeks, and 3 and 6 months post-operatively (reference range 2.10-2.55mmol/L).
Secondary outcome [1] 306901 0
The incidence of symptomatic hypocalcaemia (defined as any one of positive Chvostek’s sign, tetany, perioral paraesthesia or palpitations confirmed with ECG changes associated with any corrected calcium measurement below 2.10 mmol/L).
Timepoint [1] 306901 0
At 6 hours, days 1, 2, 3 (if still in hospital), 1 week, 2 weeks, 4 weeks, and 3 and 6 months post-operatively
Secondary outcome [2] 306902 0
The incidence of permanent hypoparathyroidsm (defined as a parathyroid blood level of <1.1 pmol/L (lower end of normal range) and requiring ongoing supplementation with 1,25(OH)D3 to maintain a corrected calcium level within the normal range
Timepoint [2] 306902 0
At 6 hours, days 1, 2, 3 (if still in hospital), 1 week, 2 weeks, 4 weeks, and 3 and 6 months post-operatively.
Secondary outcome [3] 306903 0
The dose of calcium and calcitriol as recorded in patient medical record, and prescribed as an outpatient.
Timepoint [3] 306903 0
At day 1, day 2 day 3, 1 week, 2 weeks and 4 weeks from date of surgery.
Secondary outcome [4] 306904 0
Length of inpatient hospital stay in days.
Timepoint [4] 306904 0
Prior to discharge post-operatively.
Secondary outcome [5] 306905 0
Change in parathyroid hormone blood levels from baseline.
Timepoint [5] 306905 0
Days one and two post-operatively.

Key inclusion criteria
Patients undergoing total thyroidectomy for any cause, able to provide written informed consent.
Must be able to complete follow-up.
Minimum age
18 Years
Maximum age
No limit
Both males and females
Can healthy volunteers participate?
Key exclusion criteria
-Current treatment for vitamin D deficiency at time of assessment with any form of vitamin D supplementation
-Chronic kidney disease (eGFR <60)
-Need for urgent surgery precluding completion of the intervention course
-Known primary parathyroid disease
-Current treatment with bisphosphonates
-Known severe liver disease (previous INR >1.4 without anticoagulant treatment in the presence of known liver disease, or Bilirubin > 40 in the presence of obstructive LFT profile )
-Hypercalcaemia (>2.55nmol/L) on initial pre-operative blood tests.
Refuse or are unable to provide written consent to participate

Study design
Purpose of the study
Allocation to intervention
Randomised controlled trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
After written informed consent has been provided, the Research Nurse will randomise the participant via a username and password protected web-based system. A Pharmacist will provide the corresponding allocated drug pack to the participant.
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Randomisation will be computer generated randomisation to control and intervention in a 1:1 ratio.
Masking / blinding
Blinded (masking used)
Who is / are masked / blinded?
The people receiving the treatment/s
The people administering the treatment/s
The people assessing the outcomes
The people analysing the results/data
Intervention assignment
Other design features
Phase 3
Type of endpoint(s)
Statistical methods / analysis
The predicted rate of post-operative hypocalcaemia in a general population undergoing thyroidectomy is between 25 and 30%. As this study is using a more sensitive definition of hypocalcaemia, we can expect a slightly higher incidence and therefore have used 30% as the expected incidence for our control group.
Assuming correction of deficiency between 50 and 75nmols/L, and using a conservative numbers based on prior studies we estimate an incidence on the treatment group of around 10%
Using these numbers, the required sample size to reach signifiacance (alpha 0.05 and beta 0.8) is 72 per arm. After allowing for a 10% dropout rate the sample size is 160 in total.
Categorical data will be analysed using a Chi square test and Fisher’s exact test. Continuous data will be analysed using the Student’s t-test. Furthermore, the treatment groups will be analysed in subgroups (quartiles) according to pre-treatment vitamin D level.

Recruitment status
Date of first participant enrolment
Date of last participant enrolment
Date of last data collection
Sample size
Accrual to date
Recruitment in Australia
Recruitment state(s)
Recruitment hospital [1] 2099 0
John Hunter Hospital Royal Newcastle Centre - New Lambton
Recruitment hospital [2] 2100 0
Newcastle Private Hospital - New Lambton Heights
Recruitment hospital [3] 2102 0
Lingard Private Hospital - Merewether
Recruitment postcode(s) [1] 7788 0
2305 - New Lambton
Recruitment postcode(s) [2] 7791 0
2305 - New Lambton Heights
Recruitment postcode(s) [3] 7793 0
2291 - Merewether

Funding & Sponsors
Funding source category [1] 288743 0
Name [1] 288743 0
John Hunter Hospital Staff Specialist Grants
Address [1] 288743 0
Locked Bag 1
Hunter Region Mail Centre NSW 2310

Country [1] 288743 0
Primary sponsor type
Hunter New England Local Health District
Locked Bag 1
Hunter Region Mail Centre NSW 2310
Secondary sponsor category [1] 287438 0
Name [1] 287438 0
Address [1] 287438 0
Country [1] 287438 0

Ethics approval
Ethics application status
Ethics committee name [1] 290576 0
Hunter New England Human Research Ethics Committee
Ethics committee address [1] 290576 0
Locked Bag 1
New Lambton NSW 2305
Ethics committee country [1] 290576 0
Date submitted for ethics approval [1] 290576 0
Approval date [1] 290576 0
Ethics approval number [1] 290576 0

Brief summary
Surgical removal of the thyroid gland is a relatively safe procedure, but can be associated with a number of specific complications. The parathyroid glands are close to the thyroid gland and can be affected by the surgery. These glands help to maintain calcium levels in the blood and damage to these glands from the surgery can result in low blood calcium levels. Low calcium levels can result in tingling, numbness and muscle cramps. The condition is usually treated with Vitamin D and calcium supplements after it occurs and may prolong the length of stay in hospital.
Vitamin D is a very important vitamin that helps to control bone and calium metabolism in the body. This study wants to see if by giving Vitamin D before the surgery low calcium levels can be prevented.
Trial website
Trial related presentations / publications
Public notes

Principal investigator
Name 37326 0
Dr Cino Bendinelli
Address 37326 0
Division of Surgery
John Hunter Hospital
Locked Bag 1
Hunter Region Mail Centre NSW 2310
Country 37326 0
Phone 37326 0
+61 2 49855153
Fax 37326 0
+61 2 49214274
Email 37326 0
Contact person for public queries
Name 37327 0
Ms Rosemary Carroll
Address 37327 0
Division of Surgery
John Hunter Hospital
Locked Bag 1
Hunter Region Mail Centre NSW 2310
Country 37327 0
Phone 37327 0
+61 2 49855153
Fax 37327 0
Email 37327 0
Contact person for scientific queries
Name 37328 0
Dr Cino Bendinelli
Address 37328 0
Division of Surgery
John Hunter Hospital
Locked Bag 1
Hunter Region Mail Centre NSW 2310
Country 37328 0
Phone 37328 0
+61 2 49855153
Fax 37328 0
Email 37328 0

No information has been provided regarding IPD availability
Summary results
Have study results been published in a peer-reviewed journal?
Other publications
Have study results been made publicly available in another format?
Results – basic reporting
Results – plain English summary