Why TSH test results can lead to over-testing, over-treatment

Fatigue, weight gain, constipation, dry skin. These are all symptoms that could mean hypothyroidism, and GPs may get requests from symptomatic patients for a thyroid test.
 
But, as detailed in the college’s First do no harm: A guide to choosing wisely, there can be harms associated with treating elevated thyroid stimulating hormone (TSH) levels.
 
For example, one of the potential outcomes of thyroid tests is subclinical hypothyroidism – a biochemical diagnosis defined as an elevated serum TSH concentration with a serum FT4 concentration within the normal range.
 
This condition may develop into overt hypothyroidism, but in most cases the TSH level is temporarily high and will resolve itself in a few months. Therefore, treating subclinical hypothyroidism may lead to wastage and unnecessary patient harms, which is why the RACGP does not recommend routine thyroid function testing in non-pregnant women and well adults, while thyroid imaging is not required unless a palpable neck mass can be felt.
 
It is also why one of the initial five topics in the First do no harm guide is management of subclinical hypothyroidism, which GPs can create a quick log of to self-record CPD points.
 
Dr Michael Tam, co-Chair of the First do no harm Expert Steering Group and member of the RACGP Expert Committee – Quality Care (REC–QC), told newsGP that in many ways subclinical hypothyroidism is ‘not a disease’.
 
‘Rather [it is] numbers outside of reference ranges on a blood test,’ he said.
 
‘Oftentimes, this will be transitory and have no clinical implications for the patient. However, in the context that the thyroid can be implicated in a wide variety of non-specific symptoms.
 
‘This creates a situation where minor thyroid blood test changes can result in over-testing, overtreatment, and over-medicalisation.
 
‘One of the principal goals of the First do no harm guideline is to support improved patient–doctor interactions, especially in situations where there may be conflicts in expectations and agendas between patients and their GPs.’ 
 
To date, the managing subclinical hypothyroidism resource has been the most popular topic among GPs, which Dr Tam says could be because GPs encountering mildly abnormal thyroid tests is ‘a common occurrence’ in general practice. 
 
‘Furthermore, it’s not uncommon for our patients to express worries and concerns about their thyroid function,’ he said.
 
While TSH levels can temporarily change or increase for a number of reasons including illness, medicines, supplements, age and gender – according to the First do no harm resource – treating it may not improve symptoms, but can instead lead to waste of money and resources, and harms such as increased risk of atrial fibrillation, osteoporosis and fractures.
 
Some symptoms such as fatigue, weight gain and dry skin can be non-specific for hypothyroidism and can often be attributed to lifestyle factors. Therefore, the RACGP recommends GPs conduct a review of lifestyle factors and provide appropriate interventions relating to physical activity, nutrition, sleep, hygiene, alcohol intake and mental health.
 
If symptoms do not improve with management, GPs should consider an alternative diagnosis.
 
When it comes to testing and management of thyroid issues, Dr Tam said there are two challenges. 
 
‘Firstly, are some technical complexities to the testing and interpretation of the results,’ he said. 
 
‘Secondly, communicating these complexities to patients is not simple, especially where an individual may hold established mechanistic ideas about their thyroid and the contribution of this to their health.’ 
 
While the clinician-facing part of the resource provides clinical guidance in a ‘simple and accessible format’, Dr Tam says GPs can direct patients to the accompanying part of the resource which provides a patient-centred explanation of subclinical hypothyroidism, and discuss together.
 
REC–QC Chair and Expert Steering Group co-Chair Professor Mark Morgan told newsGP the ‘traffic light’ system of the First do no harm resources provides recommendations to be used in general practice consultations.
 
‘All of the guides are designed to be quick and easy to use,’ he said.
 
‘The key recommendations are presented as traffic lights: Do this for most people [green], Do this in particular circumstances [orange] and Don’t routinely do this [red].’
 
Each topic, as part of the library of resources, will grow with new entries and is mirrored by a patient-facing resource that explains to patients why GPs are making their recommendations.
 
Dr Tam says that First do no harm is a resource designed to be ‘helpful and pragmatic’, and welcomes GP feedback whether any of the topics could be improved.
 
Thyroid tests will also be covered in the updated 10th edition Guidelines for preventive activities in general practice (Red Book), which will be launched at WONCA 2023 in October.
 
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