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 28women/3men. The dose range of NDT was
60mg-180mg daily. Age range was 26-77 years with length of time since
diagnosis with hypothyroidism ranging from 2-40 years. One person
discontinued the NDT because of lack of response; 2 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<0.001.
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<0.001. 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<0.001).
Conclusion Significant symptomatic benefit and improvement in QOL was
experienced by people with a history of levothyroxine unresponsive
hypothyroidism, suggesting the need for further evaluation of NDT in
this context.