randomized controlled trial <\/a>assessed the effect of levothyroxine therapy in older adults with subclinical hypothyroidism, finding no clear benefit.<\/p>\nDr Geoffrey Modest<\/p>\n
\n737 adults > 65 who had persistent subclinical hypothyroidism were randomized to levothyroxine 50 \u00b5g a day, or 25 \u00b5g if their body weight were\u00a0<50 kg or had coronary heart disease, with subsequent dose adjustment to achieve a TSH between 0.4 and 4.6 or placebo.( Subclinical hypothyroidism was defined as TSH of 4.60-19.99, with a free thyroxine level within the normal reference range.<\/p>\n
<\/p>\n
Primary outcomes were changes in the Hypothyroid Symptoms score and in the\u00a0Tiredness score on the thyroid related quality-of-life questionnaire, at one year.<\/p>\n
<\/p>\n
Results:<\/h5>\n
Mean TSH level decreased from 6.4 to 5.5 in the placebo group as compared to 3.6 in the levothyroxine group. This was achieved within 6-8 weeks after starting the medication. There was no difference in the mean change at one year in the Hypothyroid Symptom score (0.2 for each group). There was no significant difference in the change\u00a0in the\u00a0Tiredness score (3.2 in those on levothyroxine, 3.8 in those on placebo). For secondary outcomes and adverse events there was\u00a0 no difference<\/p>\n
<\/p>\n
Commentary:<\/h5>\n
Subclinical hypothyroidism is common, between 8 and 18% of adults > 65yrs.\u00a0To me, there is a fundamental contradiction in\u00a0the term “subclinical hypothyroidism”, since the normal limits of free T4 level reflect the bell-shaped curve of the community\u00a0lab values, whereas TSH reflects the individual person’s response to their own circulating hormone\u00a0levels. And patients may not be asymptomatic (ie “subclinical”). Subclinical hypothyroidism, therefore, I think, just reflects a low level of hypothyroidism, such that depression of T4 levels still remains within the community norm, but still, could have effects on that individual’s body.<\/p>\n
<\/p>\n
About half of the patients with subclinical hypothyroidism will progress to overt hypothyroidism with a low serum thyroxine level over 10 to 20 years, with an annual progression rate of 2 to 4%. However, some also have spontaneous recovery, less likely in those that are anti-TPO antibody positive<\/p>\n
<\/p>\n
The median achieved TSH level was 3.6, and some people believe that a more reasonable target is between 0.4 and 2.5 (i.e., it is possible that there would have been a measurable effect if they had achieved the lower and perhaps optimal TSH concentration) Hypothyroid symptom levels at trial entry were also quite low to begin with. The trial was underpowered to detect an effect on cardiovascular events or mortality. They did not measure thyroid antibody levels (which do predict to some extent which patients are more likely to progress to hypothyroidism)<\/p>\n
<\/p>\n
They also did not find any difference in the speed of information processing, which has been found to be slowed in persons with subclinical hypothyroidism. However they did not assess other measures of cognitive function, though these are typically pretty blunt instruments (MMSE, MOCA, etc)\u00a0and might not pick up very subtle though potentially important changes\u00a0for the person and family\/supports. But\u00a0treating the\u00a0subclinical hypothyroidism might still\u00a0make a real difference for the individual, especially in the long-term (and a 65-year old in otherwise good health has a 20ish year life expectancy)<\/p>\n
<\/p>\n
So, what is one to do\u00a0with older patients who have\u00a0subclinical hypothyroidism? The answer is not entirely clear, and this study really only\u00a0adds the finding that short-term treatment of essentially asymptomatic patients with minimal laboratory abnormalities\u00a0suggesting\u00a0hypothyroidism does not seem to be\u00a0effective. And I am particularly\u00a0concerned about the potential links\u00a0with atherosclerosis and cognitive decline.\u00a0 My sense is that it does seem reasonable to treat people with higher TSH levels (e.g.>10) since they have a higher likelihood of progressing to overt hypothyroidism.\u00a0In those with lower TSH levels, it might be reasonable to check anti-TPO levels and treat those patients. It also might be reasonable to treat those who are more symptomatic than in this trial. But, overall, if one elects not to treat, it does make sense to follow these patients closely to see if they progress to more thyroid dysfunction. But one concern I have is that the usual\u00a0symptoms of hypothyroidism, on the one hand, are pretty nonspecific, and, on the other hand,\u00a0in many cases reveal themselves so slowly over time that patients may accommodate to them and not even notice them (though their treatment might still positively affect their quality-of-life).<\/p>\n
<\/p>\n","protected":false},"excerpt":{"rendered":"
?thyroid meds for subclinical hypothyroidism in older adults […]<\/p>\n
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