NICE assesses the evidence for puberty blockers and hormones

In March 2021, two assessments by the UK’s National Institute for Health and Care Excellence, known as NICE, were published. In 2020, the institute had already reviewed all available research on puberty blockers and sex hormones in minors with gender dysphoria.

The assignment

NHS England commissioned the reviews as part of the independent inquiry led by paediatrician Hilary Cass, later known as the Cass Review. The assessment of puberty blockers is described in the archive as NICE review (UK, 2020). NICE assesses which treatments are supported by sufficient evidence for the UK healthcare system, using an established method to weigh the certainty of evidence.

Puberty blockers

According to NICE, the studies showed little or no change in gender dysphoria, mental health, body image and social functioning. Where a change was reported, it could also have been caused by chance or bias. The certainty of the evidence was rated very low for all outcomes.

Sex hormones

For sex hormones, the studies did provide indications of an improvement in psychological wellbeing. Here too, however, the certainty was very low: the studies were small, had no control group and followed the young people for only a short time.

What NICE is

NICE was established in 1999 to assess which treatments the UK healthcare system should provide. The institute weighs the effectiveness, safety and cost of medicines and treatments, and its assessments carry authority in England. NICE is known internationally for its rigorous methodology and is widely cited outside the United Kingdom as well.

How the certainty of evidence is assessed

NICE used the GRADE methodology. It has four levels of certainty: high, moderate, low and very low; more information is available under the evidence pyramid in gender care. A study in which patients are randomly assigned to a treated and an untreated group starts at a high level. A study that follows only treated patients starts at a low level and is downgraded further if the group is small, many participants drop out or other explanations for the outcome have not been ruled out. Very low does not mean that a treatment does not work. It means that the study does not show whether it works.

How much research there was

For puberty blockers, NICE found nine studies that met its requirements, and ten for sex hormones. Without exception, these were small studies with no control group. The studies assessed also included the Amsterdam study; see the 2011 outcome study. There was very little research available on the effects on bones, brain development and fertility.

The reactions

Clinicians who support this care argued that randomised research in this group is difficult to carry out and, in their view, unethical, and that many other treatments for children are also supported by low-certainty evidence. Others felt that an invasive treatment with permanent consequences requires stronger evidence than a treatment that can easily be discontinued.

Significance

The NICE assessments were the first in which an authoritative institution outside gender care itself evaluated the evidence against the usual medical standard. Earlier guidelines had been drawn up by clinicians working in the field. The fact that an institute that routinely assesses whether cancer medicines and heart surgery are sufficiently supported by evidence reached this conclusion made it difficult for policymakers to set the findings aside. Finland had reached a similar conclusion a year earlier; see the Finnish recommendation.

The assessments were published several months after the ruling in Bell v Tavistock and reinforced doubts about the evidence base. They became one of the building blocks of the Cass Review, for which the University of York later conducted new and more extensive literature reviews. More about UK policy can be found on the page about gender care in the United Kingdom.