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.

Introduction: The approach to thyroid hormone replacement varies across centres but the extent and determinants of variation is unclear. We evaluated geographical variation in levothyroxine (LT4) and liothyronine (LT3) prescribing across General Practices in England and analysed the relationship of prescribing patterns to clinical and socioeconomic factors. Methods: Data was downloaded from the NHS monthly General Practice Prescribing Data in England for the period 2011-2020. Results Overall, 0.5% of levothyroxine treated patients continue to receive liothyronine. All Clinical Commission Groups (CCGs) in England continue to have at least one liothyronine prescribing practice and 48.5% of English general practices prescribed liothyronine in 2019-20. Factors strongly influencing more levothyroxine prescribing (model accounted for 62% of variance) were the CCG to which the practice belonged and the proportion of people with diabetes registered on the practice list plus antidepressant prescribing, with socioeconomic disadvantage associated with less levothyroxine prescribing. For liothyronine prescribing (model accounted for 17% of variance), factors that were associated with increased levels of liothyronine prescribing were antidepressant prescribing and % of type 2 diabetes mellitus individuals achieving HbA1c control of 58mmol/mol or less. Factors that were associated with reduced levels of liothyronine prescribing included smoking and higher obesity rates. Conclusion: In spite of strenuous attempts to limit prescribing of liothyronine in general practice a significant number of patients continue to receive this therapy, although there is significant geographical variation in the prescribing of this as for levothyroxine, with specific general practice and CCG related factors influencing prescribing of both levothyroxine and liothyronine.