Patients Say Desiccated Thyroid Better Than Standard Therapy
People with hypothyroidism who choose desiccated thyroid extract (DTE) over levothyroxine alone perceive that it works better but patients may not be aware of the risks, new research suggests.
Those were among the findings from qualitative analyses of nearly 700 online posts from three popular online hypothyroidism forums, which found that 75% of patients felt they fared better on DTE than the standard therapy of levothyroxine (LT4).
The results were to be presented at the Endocrine Society's annual meeting in late March, but the meeting was canceled because of the COVID-19 pandemic. They were subsequently published online April 3 in Medicina by Freddy J.K. Toloza, MD, a postdoctoral research fellow at the University of Arkansas for Medical Sciences, Little Rock, and a research collaborator at the Mayo Clinic, Rochester, Minnesota, and colleagues.
Made from desiccated pig thyroid glands, DTE is not approved by the US Food and Drug Administration because it pre-dates the agency, but it was grandfathered in and is sold legally by prescription under the names Nature Thyroid, Thyroid USP, and Armour Thyroid.
DTE is currently used by an estimated 10% to 29% of patients with hypothyroidism, despite concerns about the risk for hyperthyroidism-associated side effects.
"Current [American Thyroid Association] guidelines strongly suggest the use of levothyroxine over DTE as thyroid replacement therapy. We agree with this recommendation given concerns about DTE's side effects," Toloza told Medscape Medical News.
"Nevertheless, additional research should be conducted to understand if this recommendation applies to all hypothyroid patients," he added, and for those patients who are taking DTE, more research is required to determine who is at risk of side effects and methods to prevent these.
Toloza said that patients with hypothyroidism who take DTE frequently described a lack of individualized treatments and a feeling of not been listened to as issues influencing their choice.
"These findings reinforce the need for patient-centered approaches in current clinical practices. Clinicians need to carefully listen to their patients and consider their individual needs and the context of every patient," he noted.
A Select Group of Patients Do Better on Combined T4/T3
Asked to comment, endocrinologist Rachel Pessah-Pollack, MD, of New York University Langone Health, told Medscape Medical News, "Animal-derived desiccated thyroid hormone contains both T4 and T3. We typically do not recommend using this because it can vary in concentration, meaning that the actual preparation is not physiologic."
Pessah-Pollack, a coauthor of the 2012 joint clinical practice guidelines on hypothyroidism by the American Thyroid Association and American Association of Clinical Endocrinologists, added that one of the major concerns about using DTE is the risk for iatrogenic hyperthyroidism, potentially leading to atrial fibrillation and fractures.
"That is one of the main factors that drive many professional societies to really use caution regarding DTE. That's also why major societies recommend against using DTE...based on the evidence to date," she said.
The whole issue of "combination therapy" in hypothyroidism is contentious, however. Physicians can also prescribe a "combination" of synthetic levothyroxine (LT4) and triiodothyronine (LT3) treatment; this, along with use of DTE products, has been a subject of debate for many years.
The current (2014) American Thyroid Association guidelines do not specifically rule out use of synthetic LT4/LT3 therapy, rather they "recommend only against the routine use of combination therapy." And although they don't expressly endorse use of DTE, they removed a statement saying it "should not be used."
"There is definitely a select group of patients who do better on combined T4/T3 treatment, and we're still trying to delineate who that population is," Pessah-Pollack told Medscape Medical News.
"As long as these patients are closely monitored and aware of the risk of hyperthyroidism and have their levels followed to ensure that they're not hyperthyroid, in select cases this is appropriate."
"But, first-line is ensuring that a good evaluation occurs...Clearly this helps us understand that we do need more studies in this area — well-designed, blinded studies to really help us get to the bottom of this controversy."
Those Taking DTE Cite Improved Symptoms, Well-Being
Toloza and colleagues analyzed 673 posts from three online forums, WebMD (Medscape's parent company), PatientsLikeMe, and Drugs.com, selected from an initial 1235 posts because they included more complete information.
About half (51%, n = 257) of patients had primary hypothyroidism/Hashimoto's thyroiditis, 25% (n = 126) had postsurgical hypothyroidism, and 16% (n = 81) had postablation hypothyroidism. Among the 172 posts in which DTE dose information was available, the mean dose was 84.1 mg/day. Treatment duration ranged widely, from 2 weeks to 45 years.
Among the posts describing the source of the DTE prescription, the initial interest was driven mainly by the patient in 54% (n = 88), while 46% (n = 74) said that a clinician drove their interest in trying DTE. (The type of clinician was not reported.)
Among posts mentioning thesource of DTE, local pharmacies were the most common (63%, n = 75), followed by pharmacies outside the United States (31%, n = 37), and online (6%, n = 7).
Previous thyroid treatments were mentioned in 300 posts, of which 93% mentioned LT4 monotherapy.
Among the reasons for changing to DTE were no improvement in clinical symptoms (47%, n = 75), development of side effects (24%, n = 38), no change in overall well-being (22%, n = 36), and no changes in laboratory workup (7%, n = 12).
Perceived benefits of DTE included improvement in clinical symptoms (56%, n = 155), change in overall well-being (34%, n = 94), possibility of reaching previous health status (7%, n = 19), and low cost compared with previous treatment (3%, n = 8).
Specific symptoms reported to have improved included fatigue (28%, n = 43), weight gain (17%, n = 26), and neurocognitive symptoms (5%, n = 8). The average time to notice benefits with DTE was about 30 days but ranged widely from 2 days to 4 months.
The majority of posts (77%, n = 99) stated that DTE was more effective than their previous therapy, while 13% (n = 17) described it as equally effective and 10% (n = 13) said it was less effective.
Side effects of DTE were described by 20% (n = 136), including weight loss (15%), fatigue (11%), palpitations (11%), heat intolerance (11%), sleep disturbances (10%), high blood pressure (7%), and hair loss (5%).
"Doctors Think They Know How u Feel"
A qualitative analysis of the posts yielded five major themes: experience with previous therapies before starting DTE, perceived effectiveness and benefits of DTE, DTE side effects, need for individualized therapy for hypothyroidism, and barriers to obtaining DTE.
One patient posted: "Synthroid [levothyroxine] did not help...and gives me bad side effects...my endocrinologist blamed all side effects on everything except the Synthroid."
Another wrote, "It [Armour] changed my life...I'm glad I found a medication that makes me feel normal again...all have improved; moods, skin (no itching), no headaches, goiter is down."
Others cited the lower cost of Armour compared with Synthroid.
However, some expressed negative experiences with DTE, such as, "My doctor expected that this medication would help me with brain fog, energy, and tiredness. I experienced the opposite."
And some couldn't obtain it. One wrote, "Doctors think they know how u feel and do not even tell you about Armour. I asked my doctor and was told there was not enough studies on it to show its effectiveness."
Better Evaluation, More Data Needed
Pessah-Pollack pointed out that the study data don't address whether patients' initially prescribed levothyroxine doses were optimal, and noted that sometimes changes are needed, such as during pregnancy, following weight gain, or if the patient is taking other certain medications.
"It's unclear from patient-reported symptoms whether or not they actually had an evaluation of their thyroid levels to ensure that their dose of thyroid hormone was correct before switching over to T4/T3 replacement...There are many factors that need to be taken into account before we decide that the medication itself isn't working."
What's sorely needed, she said, are "well-designed, blinded studies that look at this controversy."
"Here, we don't know why patients are feeling better...We need to do additional work including validated symptom questionnaires and comparing thyroid levels of patients who are on Armour thyroid with those on levothyroxine monotherapy."
Toloza agrees: "It is not possible to say that DTE is working better for the user due to the limitations and the nature of the data used in our study."
"However, our findings are in-line with previously published research, which has shown that a subset of patients may prefer DTE to levothyroxine and have higher satisfaction with this treatment. Nevertheless, the reason behind this is still not well understood," and it should be further investigated.
Pessah-Pollack has reported being an advisor for Boehringer Ingelheim-Eli Lilly and Radius Health, and a moderator for Sanofi.
Medicina. Published online April 3, 2020. Abstract