Thyroid hormones should not be used to treat people with mild hypothyroidism according to new guidance published in the BMJ.
The research suggested that if implemented, this recommendation ‘may substantially alter prescribing trends’, which show that thyroid medicines are increasingly being prescribed, ‘most probably due to SCH’ (subclinical hypothyroidism).
The research concluded almost no one with the condition would benefit from treatment.
The recommendations have been put together in response to a systematic review published last year which found thyroid hormone therapy did not improve quality of life or symptoms in those with subclinical disease.
An international panel reviewing the research strongly recommended not prescribing thyroxine in people who have slightly raised thyroid stimulating hormone (TSH) levels but normal thyroid hormone.
It goes against current guidelines which tend to recommend thyroid hormones for adults with TSH levels >10 mIU/L and for people with lower TSH values who are young, symptomatic, or have specific indications for prescribing, the expert panel said.
It has been estimated that subclinical hypothyroidism affects about 5% of the general adult population and 10-15% of the elderly, some who will show no symptoms.
In the UK, around 25% of adults have thyroid function tests every year and if adopted the guidelines could ‘substantially alter prescribing trends’, the panel said.
The latest evidence suggests there is no overall benefit from thyroid hormone treatment on fatigue, low mood, weight gain, in these patients, the guidance said.
In addition, the lifelong need for check-ups is ‘burdensome’ said the panel who concluded they could also not rule out the possibility of harm.
The new recommendations do not apply to women who are trying to become pregnant or patients with particularly high TSH levels (above 20 mIU/L), the panel said.
More than 32 million prescriptions for levothyroxine were issued in England in 2018, NHS figures show.
More research is needed to determine if there is a subgroup of patients who may benefit, the panel added.
‘Instead, clinicians should monitor the progression or resolution of the thyroid dysfunction in these adults,’ they advised.
Professor Helen Stokes-Lampard, chair of the Royal College of GPs, said: ‘Thyroid hormones are powerful drugs and GPs will only ever prescribe them if we think they are of genuine benefit to the person sitting in front of us, particularly as it usually means taking the tablets and being monitored in the long-term.
‘If evidence shows that they are not going to be of benefit to our patients, it is important that we know this and that it is reflected in the clinical guidelines that inform our decision-making.’
She added that the authors of the new guidance make ‘a powerful case’.
‘It is important that this new research is taken on board as clinical guidelines are updated and developed, in the best interests of our patients. It is also important that patients do not suddenly stop taking their thyroxine medication, but that they discuss this with their GP at their next routine medication review.’