Subclinical Hypothyroidism for the Elderly Population

Hypothyroidism is a common condition affecting many individuals.  Symptoms of hypothyroidism can be very non-specific and include the following: fatigue, cold intolerance, constipation, and weight gain. According to Up-to-date (accessed on May 6, 2017), primary hypothyroidism is characterized by a high serum thyroid-stimulating hormone (TSH) concentration and a low serum free thyroxine (T4) concentration, whereas subclinical hypothyroidism is defined biochemically as a normal free T4 concentration with an elevated TSH concentration.

Given we tend to only screen with TSH, we often cannot differentiate between primary hypothyroidism and subclinical hypothyroidism.  Yet in the elderly population, subclinical hypothyroidism is very common.  Some clinicians would argue that treatment with levothyroxine may not be necessary.

This question was evaluated in the Trust Thyroid Trial, of which the results were published recently in the New England Journal of Medicine here.

Here are some highlights of the study:

Study Objective:

  • To determine whether there are clinical benefits from levothyroxine replacement in older persons with subclinical hypothyroidism.

Methodologies:

  • A double-blind, randomized, placebo-controlled, parallel-group trial involving 737 adults who were at least 65 years of age and who had persistent subclinical hypothyrodism (TSH 4.6-19.99mIU/L, free thyroxine level within the reference range).
  • The main exclusion criteria were a current prescription for levothyroxine, antithyroid drugs, amiodarone or lithium; thyroid surgery or receipt of radioactive iodine within the previous 12 months, dementia, hospitalization for a major illness or an elective surgery within the previous 4 weeks, an acute coronary syndrome within the previous 4 weeks and terminal illness.
  • 368 adults were assigned to treatment group; 369 adults were assigned to placebo group.
  • Two primary outcomes were measured at baseline and at 1 year for the following:
    • the change in the Hypothyoridism symptoms score and
    • The Tiredness score on a thyroid-related quality-of-life questionnaire

Main Results

  • Hypothyroidism Symptoms Score at 1 year
    • Placebo group: 16.7± 17.5
    • Levothyroxine group: 16.6± 16.9
    • Difference (0.0 [-2.0 to 2.1]), p =0.99
  • Tiredness Score at 1 year
    • Placebo group: 28.6± 19.5
    • Levothyroxine group: 28.7± 20.2
    • Difference (0.4 [-2.1 to 2.9]), p = 0.77

Conclusions:

  • Given there were no differences in the primary outcomes, the authors concluded that there was no apparent benefit in levothyroxine replacement therapy in older persons with subclinical hypothroidism.

Here are some of my thoughts:

In practice, I do see some elderly individuals present with elevated TSH but the repeat TSH with T4 results often confirm subclinical hypothyroidism.  I do agree that not everyone requires levothyroxine replacement, nor an increase in their existing levothyroxine dose. However, repeat monitoring every 3-6months may be warranted as some individuals do eventually develop primary hypothyroidism for which levothyroxine replacement would be indicated.

I don’t always jump to recommend increasing levothyroxine dose for an elevated TSH in the following scenarios:

  • New admission to a long term care facility due to progressive dementia. In this situation, the patient’s history is not reliable including the compliance history. Hence there is a good chance that the TSH is elevated because of non-compliance and may self-correct when the medication will be reliably administered in the long term care facility by registered staff.
  • Concurrent levothyroxine with calcium, iron or other multivitamin supplements. Levothyroxine may not be well absorbed if administered at the same time with these supplements. Hence, the first thing is to try changing the timing of administration as this may resolve the concern and correct for the TSH gradually.

What do you think? Do you encounter patients with hypothyroidism in your practice? How do you manage individuals with subclinical hypothyroidism?

Looking forward to hearing your thoughts. As always, thank you for dropping by and reading my post.

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drugopinions

My name is Cynthia Leung and I am a practicing pharmacist in Kingston Ontario, Canada. This blog is for me to share my ideas, opinions and perspectives on how medications are used in our health care system. Note that these posts are my own opinions and do not represent the opinions of my current or former employers and / or organizations that I may belong to. Any possible case scenarios described in my posts would be modified to maintain patient confidentiality. This blog is not a platform for professional advise for patients or health care providers and the content is not meant to support any clinical decisions or replace professional opinions. Also the images are either taken or created by the author, or adapted with permission. I hope you will enjoy reading my posts!

4 thoughts on “Subclinical Hypothyroidism for the Elderly Population”

  1. All great points… being vigilant in each case is of value.. especially in cases where the elders personality or liveliness has changed.. and is noted by staff or family.

    Liked by 1 person

  2. Why is the patient being tested? Is it for symptoms of hypothyroidism or for another reason eg atrial fibrillatio, tachycardia, hyperhidrosis, for concern for hidden hyperthyroidism, or “routine “screening ? The values range of 5-10 along with no symptoms of hypothroidism is what I called subclinical hypothyroidism. I would always discuss with the patient the values, and usually came up with a joint decision not to treat but to explain the need to keep a lookout for symptoms, and for periodic rechecks as you have said.

    Of course with symptoms(fatigue, constipation, weight gain,dry skin etc,) its not subclinical hypothyroidism and I treated.

    Liked by 1 person

    1. You raised a lot of great points. Treat the patient, not the number. OTher than a baseline TSH, I don’t recommend any routine monitoring unless the patient is on levothyroxine. Also if there is concern with mood changes or depression, it would be a good idea to recheck the TSH.

      Like

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