Iodized salt improves the effectiveness of L-thyroxine therapy after surgery for nontoxic goitre: a prospective and randomized study

[Surgical resection of the thyroid and parathyroid glands]

The main indication for surgery of the thyroid gland is the resection of nodular, suspicious or hyperfunctioning tissue. Following thyroidectomy, L-thyroxine therapy is initiated adjusted to the remnant thyroid function. To prevent recurrence of a multinodular goiter, supplementation with iodine is strongly recommended. The management of patients with differentiated thyroid cancer depends on risk stratification. Although large prospective studies are missing, low-risk patients probably do not benefit from total thyroid ablation and lifelong thyroxine suppression therapy. As a result of impaired parathyroid function or resection of the parathyroid glands for hyperparathyroidism, acute or chronic hypocalcaemia can develop. If treatment with oral calcium is insufficient, the addition of a vitamin D analogue is necessary. This requires close monitoring to avoid renal or other hypercalcaemic complications.

Predictive factors for recurrence after thyroid lobectomy for unilateral non-toxic goiter in an endemic area: Results of a multivariate analysis

BACKGROUND

The aim of the study was to identify the factors that are predictive of recurrence after thyroid lobectomy for unilateral non-toxic thyroid goiter in an endemic region through a multivariate analysis.

METHODS

Two hundred sixty-eight consecutive patients who underwent thyroid lobectomy and who were evaluated by the same endocrinologist were included. Univariate and multivariate analysis analyzed the relationship between sex, age, preoperative thyroid-stimulating hormone, duration of disease, duration of levothyroxine (LT4) preoperative therapy, cytologic results, histologic results, resected thyroid weight, numbers and diameters of thyroid nodules, morphologic alterations of the remnant lobe, follow-up length, postoperative LT4 therapy, ultrasonographic evidence of recurrence, and reoperation.

RESULTS

The incidence of recurrence was 33.9% (91/268 patients) after a mean follow-up time of 79.9 months (range, 12-251 months), female sex ( P = .016), multiple nodules ( P = .017), and lack of postoperative LT4 therapy ( P = .0009) were predictive factors of recurrence. Reoperation was performed in 20 patients (7.4%); factors that were predictive of reoperation were the presence of multiple nodules ( P = .008), resected thyroid weight ( P = .00006), and lack of postoperative hormonal therapy ( P = .0005).

CONCLUSIONS

Thyroid lobectomy for unilateral non-toxic goiter, when combined with suppressive or substitutive thyroxin therapy, resulted in a low rate of recurrence and reoperation in an endemic area.

Iodised salt for preventing iodine deficiency disorders

BACKGROUND

Iodine deficiency is the main cause for potentially preventable mental retardation in childhood, as well as causing goitre and hypothyroidism in people of all ages. It is still prevalent in large parts of the world.

OBJECTIVES

To assess the effects of iodised salt in comparison with other forms of iodine supplementation or placebo in the prevention of iodine deficiency disorders.

SEARCH STRATEGY

We searched the Cochrane Library, Medline, the Register of Chinese trials developed by the Chinese Cochrane Centre, and the Chinese Med Database. We performed handsearching of a number of journals (Chinese Journal of Control of Endemic Diseases, Chinese Journal of Epidemiology, Chinese Journal of Preventive Medicine, and Studies of Trace Elements and Health up to February 2001), and searched reference lists, databases of ongoing trials and the Internet. Date of latest search: November 2001.

SELECTION CRITERIA

We included prospective controlled studies of iodised salt versus other forms of iodine supplementation or placebo in people living in areas of iodine deficiency. Studies reported mainly goitre rates and urinary iodine excretion as outcome measures.

DATA COLLECTION AND ANALYSIS

The initial data selection and quality assessment of trials was done independently by two reviewers. Subsequently, after the scope of the review was slightly widened from including only randomised controlled trials to including non-randomised prospective comparative studies, a third reviewer repeated the trials selection and quality assessment. As the studies identified were not sufficiently similar and not of sufficient quality, we did not do a meta-analysis but summarised the data in a narrative format.

MAIN RESULTS

We found six prospective controlled trials relating to our question. Four of these were described as randomised controlled trials, one was a prospective controlled trial that did not specify allocation to comparison groups, and one was a repeated cross-sectional study comparing different interventions. Comparison interventions included non-iodised salt, iodised water, iodised oil, and salt iodisation with potassium iodide versus potassium iodate. Numbers of participants in the trials ranged from 35 to 334; over 20,000 people were included in the cross-sectional study. Three studies were in children only, two investigated both groups of children and adults and one investigated pregnant women. There was a tendency towards goitre reduction with iodised salt, although this was not significant in all studies. There was also an improved iodine status in most studies (except in small children in one of the studies), although urinary iodine excretion did not always reach the levels recommended by the WHO. None of the studies observed any adverse effects of iodised salt.

REVIEWER'S CONCLUSIONS

The results suggest that iodised salt is an effective means of improving iodine status. No conclusions can be made about improvements in other, more patient-oriented outcomes, such as physical and mental development in children and mortality. None of the studies specifically investigated development of iodine-induced hyperthyroidism, which can be easily overlooked if just assessed on the basis of symptoms. High quality controlled studies investigating relevant long term outcome measures are needed to address questions of dosage and best means of iodine supplementation in different population groups and settings.