Is there a role for natural desiccated thyroid in the treatment of levothyroxine unresponsive hypothyroidism? Results from a consecutive case series

Abstract

Introduction Some levothyroxine unresponsive individuals with hypothyroidism are prescribed a natural desiccated thyroid (NDT) preparation such as Armour Thyroid® or ERFA Thyroid®. These contain a mixture of levothyroxine and liothyronine in a fixed ratio. We evaluated the response to NDT in individuals at a single endocrine centre in terms of how the change from levothyroxine to NDT impacted on their lives in relation to quality of life (QOL) and thyroid symptoms. Methods The ThyPRO39 (thyroid symptomatology) and EQ‐5D‐5L‐related QoL/EQ5D5L (generic QOL) questionnaires were administered to 31 consecutive patients who had been initiated on NDT, before initiating treatment/6 months later. Results There were 28 women and 3 men. The dose range of NDT was 60‐180 mg daily. Age range was 26‐77 years with length of time since diagnosis with hypothyroidism ranging from 2 to 40 years. One person discontinued the NDT because of lack of response; two because of cardiac symptoms. EQ‐5D‐5L utility increased from a mean (SD) of 0.214 (0.338) at baseline, to 0.606 (0.248) after 6 months; corresponding to a difference of 0.392 (95% CI 0.241‐0.542), t = 6.82, P < .001. EQ‐VAS scores increased from 33.4 (17.2) to 71.1 (17.5), a difference of 37.7 (95% CI 25.2‐50.2), t = −4.9, P < .001. ThyPRO scores showed consistent fall across all domains with the composite QoL‐impact Score improving from 68.3 (95% CI 60.9‐75.7) to 25.2 (95% CI 18.7‐31.7), a difference of 43.1 (95% CI 33‐53.2) (t = 5.6, P < .001). Conclusion Significant symptomatic benefit and improvement in QOL was experienced by people with a history of levothyroxine unresponsive hypothyroidism treated with NDT, suggesting the need for further evaluation of NDT in this context.

Effect of Radioiodine Treatment on Quality of Life in Patients with Subclinical Hyperthyroidism: A Prospective Controlled Study

“…Similarly, in a large, double-blind, randomised, placebo-controlled, parallel-group trial ThyPRO scales did not improve after treatment with LT4 in older adults with subclinical hypothyroidism [47]. In another study at least some patients with hypothyroidism unresponsive to LT4 treatment experienced significant improvement in ThyPRO scores after switching to a combination of LT4 and LT3 [48]. In a study of patients treated with antithyroid drugs, radioiodine therapy or surgery for Graves' disease, QoL impairments persisted long-term, compared to the general population, and RIT patients had the worst QoL among the treatment modes [49].…”

Implementation of thyroid-related patient-reported outcomes in routine clinical practice

“…However, patients most symptomatic on levothyroxine alone preferred and responded positively to therapy with levothyroxine + liothyronine or desiccated thyroid extract. Another recent study examined the effect of natural dessicated thyroid, as evaluated with ThyPRO-39 ( 35 ) and EQ-5D-L ( 19 ) at baseline and six months after initiation of treatment ( 46 ). Patients with levothyroxine unresponsive hypothyroidism experienced significant improvement in QoL.…”

Levothyroxine: Conventional and Novel Drug Delivery Formulations

“…Considering that the physiological ratio of T3:T4 secreted by the thyroid gland is approximately 1:14 and the residual thyroid has secretory function, a ratio between 1:8 and 1:13 may be more appropriate ( 154 ). Animal-derived DTE has also been introduced to treat refractory hypothyroidism due to combinations of T3 and T4 in a 1:4.22 ratio ( 155 ). Animal-derived DTE contains a supraphysiological amount of T3, and cardiac complications should be monitored with caution.…”