Dutch experts: evidence gender treatment insufficient

The research on which medical treatment for transgender youth in the Netherlands is based is scientifically flawed. So say four leading methodologists and a professor of remedial education to Zembla. The research is the basis for the much-vaunted Dutch Protocol, the treatment method developed by the VU University Amsterdam in the 1990s and adopted in many other Western countries.

Van Breukelen is the only expert willing to be mentioned by name. The subject is very sensitive, so the other experts want to remain anonymous.

The protocol prescribes, that at the beginning of puberty, hormone inhibitors can be given to adolescents with gender dysphoria. This stops the production of sex hormones of the unwanted sex. This would lead to better psychological well-being and decreased perceived gender dysphoria after a sex change. The experts Zembla spoke to think the evidence for this is lacking. “Scientifically insufficient,” said Gerard van Breukelen, professor of methodology at Maastricht University.

The study was published in 2011 and 2014 by child psychiatrist Annelou de Vries and her colleagues at the gender clinic of the VU Medical Centre, now the Amsterdam UMC. It forms the basis of the ‘Dutch protocol’, the method developed in the 1990s and zero by psychiatrists and endocrinologists at the VU, for treating adolescents with gender dysphoria. The Amsterdam method has been adopted in international standards. De Vries’ study is considered crucial evidence for the effectiveness of the Dutch treatment protocol.

Five experts

At Zembla’s request, five Dutch experts looked at how the research behind the protocol was carried out. They were four methodologists including two professors, a professor emeritus and an assistant professor, and a professor of remedial education.

All four methodologists specialise in assessing complex scientific studies on treatments and medication. Gerard van Breukelen, methodologist and statistician at Maastricht University, lists a number of criticisms and highlights the lack of a control group in the Amsterdam study: “There is no comparison group, and all patients who received puberty blockers also received psychological counselling at the same time, so two treatments were running side by side.” This is precisely why the lack of a control group is disastrous, says Van Breukelen. This makes it impossible to determine which treatment is effective. “You cannot answer that question without a control group, we are completely in the dark.”

Anonymous experts due to sensitivity

Van Breukelen is the only expert willing to be mentioned by name. The subject is very sensitive, so the other experts want to remain anonymous.

A methodologist at the UMC Utrecht agreed to an interview in front of Zembla’s cameras, but then received a negative advice from his hospital. He says he was told that participation would be “bad for his career”. UMC Utrecht confirms that the methodologist was advised not to speak out on the subject, ‘because there is so much sensitivity surrounding this’.

“Research evidence limited”

“The studies in this area are of low quality, and would not be accepted as evidence in other areas.”

All experts endorse criticism of the lack of a control group and of long-term follow-up studies. A few also point to the limited size of the patient group, the high dropout rate and the fact that one of the transgender youths died due to gender surgery.

A professor of methodology argues that ‘the evidence base of the study is limited’. The professor emeritus writes that De Vries’s research ‘is not a solid basis for performing radical and non-reversible medical interventions’. The professor of orthopaedagogy states that she finds this ‘insufficient evidence to give puberty inhibitors in increasing numbers’.

“Invasive treatment with lifelong consequences”

In the broadcast ‘The transgender protocol’, foreign psychiatrists also speak. In it, Riittakerttu Kaltiala, a Finnish professor of psychiatry at the University of Tampere, judges that De Vries’s research does not provide evidence for the effectiveness of the Dutch treatment protocol.

And Mikael Landén, professor of psychiatry at the University of Gothenburg, wonders: “Why are lower requirements placed on the evidence for this patient group than on the evidence for other groups? That is not fair. This is about a very invasive treatment with lifelong consequences.”

Gender clinic response

Child psychiatrist Annelou de Vries of the Amsterdam UMC, says in the broadcast that using a control group would be unethical. “That is not an option, then you withhold a treatment that you know is incredibly important for a group,” she said. But methodologists approached by Zembla argue that there are indeed alternative research methods that the gender clinic could have used.

De Vries additionally explains that a lot of additional evidence has since been published by both the Amsterdam researchers and international colleagues. But Professor Landén rejects that defence. He reviewed all relevant studies on puberty blockers at the request of the Swedish government. He did not find any evidence for the beneficial effect the inhibitors have according to the Dutch protocol. “The studies in this area are of low quality, and would not be accepted as evidence in other areas”, he said.

The UK health institute NICE also conducted such a ‘systematic review’. This showed that the evidence for the beneficial effects of puberty blockers falls into the ‘very low certainty’ category: the very lowest class of scientific evidence.

Meanwhile, Finland, Sweden, the UK, Denmark and Norway, among others, have adapted care for transgender adolescents. In these countries, puberty blockers are now prescribed only in extreme cases and only as experimental drugs.