Clinical trial NCT00871130: The Effect of Bariatric Surgery on Thyroid Function and Morphology
Official title: The Effect of Bariatric Surgery on Thyroid Function and Morphology, a Retrospective Study
Study type: OBSERVATIONAL
Overall status: COMPLETED
Conditions: Thyroid Function
Obesity
Keywords: Thyroid gland
bariatric surgery
weight loss
thyroid hormones
adult
morbid obesity
cohort
Lead sponsor: Insel Gruppe AG, University Hospital Bern
Sponsor class: OTHER
First posted: 2009-03-30
Enrollment: 300
Sex: ALL
Minimum age (years): 18
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: no
Observational model: COHORT
Time perspective: RETROSPECTIVE
Sampling method: NON_PROBABILITY_SAMPLE
Study population: All patients who have received a surgical procedure to result in desired weight reduction (gastric banding, gastric bypass or vertical gastroplasty either open or laparoscopic or a combination of any)

Brief summary: The aim is to evaluate the effect of dramatic weight loss after bariatric surgery on thyroid function (thyroid hormone levels and particulary morphological changes) in the short and long-term setting of a cross-sectional study. A particular focus will be made with regard to putting into correlation preoperative thyroid function abnormalities and postoperative changes over time with respect to the type of bariatric intervention carried out.

Detailed description: Background:

Over the last decades, there has been an increase in obesity in virtually all population groups with approximately 1.6 billion adults worldwide estimated to be overweight in 2005 and 400 million of these people qualifying as being obese.

Although hormonal disturbances may play a certain role in the development of obesity, more important are the possible consequences of obesity and the influence of surgically-induced rapid weight loss on overall endocrine function of these patients. Studies evaluating the effect of weight loss on thyroid function show inconsistent results. Whilst some authors have shown that weight loss after bariatric surgery may have a positive effect on thyroid dysfunction, especially in individuals with preoperative subclinical hypothyroidism 1 resulting in normalisation of TSH levels, others fail to show any significant postoperative changes.

Objective:

To evaluate the effect of dramatic weight loss after bariatric surgery on thyroid function (thyroid hormone levels and particularly morphological changes) in the short and long-term in the setting of a cross-sectional study. A particular focus will be made with regard to putting into correlation preoperative thyroid function abnormalities and postoperative changes over time with respect to the type of bariatric intervention carried out.

Methods:

BMI, thyroid hormones (TSH, fT3, fT4 levels), need for thyroxin substitution (or equivalent medication) as well as pre- and postoperative morphological changes in the thyroid gland (usually via sonography)and Leptin values will be assessed retrospectively.

Eligibility criteria: Inclusion Criteria:

* Patients who underwent bariatric surgery between 1998 and 2007

Exclusion Criteria

* age \>18 years

Primary outcomes:
measure: thyroid hormone levels (change in)
timeFrame: preoperative, 3, 6 and 12 months postoperative
Secondary outcomes:
measure: morphological changes of the thyroid gland
timeFrame: up to 12 months postoperatively
Other outcomes:
Locations:
city: Bern
country: Switzerland
facility: Dep.of Visceral and Transplant Surgery, Bern University Hospital
Study officials:
affiliation: Dep.of Visceral and Transplant Surgery, Bern University Hospital
name: Vanessa Banz, MD
role: PRINCIPAL_INVESTIGATOR
References:
citation: Chikunguwo S, Brethauer S, Nirujogi V, Pitt T, Udomsawaengsup S, Chand B, Schauer P. Influence of obesity and surgical weight loss on thyroid hormone levels. Surg Obes Relat Dis. 2007 Nov-Dec;3(6):631-5; discussion 635-6. doi: 10.1016/j.soard.2007.07.011.
citation: Alagna S, Cossu ML, Masala A, Atzeni MM, Ruggiu M, Satta FM, Fais E, Rovasio PP, Noya G. Evaluation of serum leptin levels and thyroid function in morbidly obese patients treated with bariatric surgery. Eat Weight Disord. 2003 Jun;8(2):95-9. doi: 10.1007/BF03324997.
citation: Reinehr T, Andler W. Thyroid hormones before and after weight loss in obesity. Arch Dis Child. 2002 Oct;87(4):320-3. doi: 10.1136/adc.87.4.320.