Frequency, determinants and costs of thyroid function testing in a laboratory serving a large population

Abstract

Objective: To assess the rationale and frequency of thyroid function testing and to analyse factors that influence serum thyrotropin (TSH) levels. Patients , Design and Main Outcome Measures: Serum TSH levels were evaluated in a hospital laboratory serving a population of 604,000 in 2018. Patients on medications or with conditions affecting thyroid function were excluded. Frequency of thyroid function testing by age and sex was assessed and relationship between serum TSH with potential predictor variables was analysed using ordinary least square regression analysis allowing for potential nonlinearity. Results: Twenty eight percent of the local population had their thyroid function tested at least once in 2018 with significant differences by sex (28.2% women vs 23.4% men) and by age groups, with less than 2% of <16-year-old and more than 50% of >80-year-old people being tested. Most of the symptoms commonly attributed to thyroid dysfunction were not higher in the thyroid dysfunction groups. Serum TSH levels were higher in older people particularly after the age of 60 years, in women (by 0.1 mIU/L), during the early hours of the morning, and in winter and spring seasons. There was remarkable uniformity in the frequency of subclinical thyroid dysfunction, as well as substantial cost savings, if TSH reference intervals were recalculated across sexes, age groups, time-periods and seasons. Conclusions: Serum TSH is frequently tested in the population but is not a good discriminant of symptoms attributed to thyroid dysfunction. Furthermore, considering the influence of factors on TSH reference limits could significantly impact patient care and resource utilisation.

Treating subclinical hypothyroidism in individuals with or without mental health problems –A Delphi based expert consensus study in two countries

“…Another study from the UK, however, examining thyroid tests in 161401 individuals, found that TSH concentrations were not a good discriminant of symptoms attributed to thyroid dysfunction. Furthermore, TSH values depended on age, sex, season and timing of sampling, which would require adjustment of TSH reference ranges ( 2 ). Finally, an international online survey of 3915 individuals with self-reported treated hypothyroidism found a 59% prevalence of probable somatic symptom disorder with a tendency to attribute persistent symptoms to hypothyroidism or its treatment ( 37 ).…”

“…Age, sex, body mass index, ethnicity, iodine intake, thyroid peroxidase antibody (TPOAb) status, and TSH cut-off point are among the factors that can affect prevalence estimates (1). Symptoms attributed to SCH are often non-specific, including tiredness/fatigue, cold intolerance, weight gain, cognitive dysfunction, depression, and anxiety (1)(2)(3). These symptoms can significantly affect well-being, leading to repeated medical consultations, request for inappropriate investigations, and dissatisfaction with treatment (3).…”

Editorial: Treatment of subclinical thyroid dysfunction in patients with comorbidities

“…There is a modest rise in serum TSH levels with age, yet the TSH reference range does not reflect this age-related increase (5). It is therefore not surprising that the prevalence of SCH rises with age and there is an attenuation of this increase when age-appropriate TSH reference ranges are utilised (6). However, randomised controlled trials of levothyroxine treatment of SCH in older people (>65 years) conducted to date have been proven to be ineffective in improving symptoms of hypothyroidism and/or quality of life (7).…”