Strategies for improved management of hypothyroidism
Management is clear-cut—yet many patients don’t reach treatment goals. To optimize quality of life, master the fine points of T4 replacement and address the impact of comorbidities.
PRACTICE RECOMMENDATIONS
› Prescribe levothyroxine (LT4) to maintain thyroid-stimulating hormone (TSH) at 4 to 7 mIU/L in select patients with primary hypothyroidism for whom that range of the serum TSH level can be considered appropriate (ie, those older than 65 years and those who have underlying coronary artery disease or another debilitating chronic disorder). A
› Counsel all women of childbearing age with primary hypothyroidism that they need to have their dosage of LT4 increased as soon as pregnancy is suspected. A
› Keep in mind that treating hypothyroidism is not always necessary in older patients who have subclinical disease and a serum TSH level < 10 mIU/L. A
Strength of recommendation (SOR)
A Good-quality patient-oriented evidence
B Inconsistent or limited-quality patient-oriented evidence
C Consensus, usual practice, opinion, disease-oriented evidence, case series
Several clinical trials addressed the question of whether residual symptoms could be resolved through LT4 + LT3 combination therapy31-39 (TABLE 434), but evidence of any consistent superiority of combination therapy was not demonstrated.35-39 In selected cases, patients might prefer the combination approach.31,33,39 The quality of life of hypothyroid patients was found to be similarly improved with LT4 or DTE, but the latter was associated with modest weight loss (approximately 4 lbs); nearly 50% of study patients preferred treatment with DTE over LT4.33 A follow-up study did not confirm weight loss with DTE, however.34
When LT4 monotherapy and LT4 + LT3 combination therapy were compared, results were mixed31-39; responsiveness to therapy containing LT3 might therefore depend on multiple variables, including genetic background, nutritional and lifestyle factors, stress, presence of comorbidities and autoimmune disorders, and other unidentified or poorly defined variables.40-48
Although combination therapy and DTE are not generally recommended over LT4 monotherapy, they might offer better options for patients who are still symptomatic when being treated with LT4 only: In a randomized, double-blind, crossover study that compared LT4 with DTE and with LT4 + LT3, one-third of the most highly symptomatic patients who had low scores on mood, cognitive, and quality-of-life assessments improved significantly after they were switched to combination therapy or DTE.34
The 2014 American Thyroid Association guidelines24 do not support routine use of LT4 + LT3 in hypothyroid patients who have residual symptoms after LT4 monotherapy; however, a therapeutic trial of LT4 + LT3, while maintaining a normal serum TSH, is reasonable in selected patients. Candidates for DTE or LT4 + LT3 might include patients who do not feel well on LT4 monotherapy, are post thyroidectomy or post radioiodine therapy, or have a low serum T3 level. DTE and combination therapy are discouraged in older patients, patients who have underlying CAD, and pregnant patients.
Special treatment circumstances
A number of patient variables have the potential to alter management strategies for hypothyroidism.18,20,23,40,49-53
Age, comorbidity. Older patients (> 65 years) and patients with cardiopulmonary disease or CAD should be treated with LT4, 25 to 50 mcg/d, initially; that dosage can be titrated upward by 12.5 to 25 mcg/d every 4 to 6 weeks until the TSH goal is reached—preferably, in the range of 4 to 8 mIU/L. An increase in the dosage of LT4 might be required in the presence of malabsorption (eg, gastrointestinal disorders, celiac disease) and in nephrotic syndrome.18,20,23
Body weight. A decrease in the dosage of LT4 might be indicated in the setting of significant weight loss (> 10% body weight).23
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