Don’t treat testosterone by the numbers, expert says

4 minute read


The controversy continues around testosterone prescribing, with new guidelines advocating an even stricter approach


 

Should testosterone be prescribed for men without a pathological cause for low levels?

The controversy continues around testosterone prescribing, with new endocrinology guidelines advocating an even stricter approach than the one taken by the government last year.

The objective of the new Endocrine Society of Australia guidelines was to discourage prescribing by numbers, i.e specific testosterone levels, said Professor David Handelsman, co-author of the guidelines.

The question to be considered when thinking of prescribing testosterone was: ‘Has this person got a reproductive disorder or not?’

“If they don’t, there’s no justification for testosterone prescribing – not on current evidence,” the professor of reproductive endocrinology and andrology at the University of Sydney said. These include primary testicular failure, and pituitary or hypothalamic or chromosomal abnormalities.

While the new guidelines were not dramatically different from the 2000 guidelines, they provided an intellectual framework for the government’s decision last year to further restrict PBS subsidies for testosterone prescribing, he said.

Previously, men were eligible for a PBS subsidy for testosterone therapy at a testosterone level of 8 nmol/L, but this was lowered to 6 nmol/L in 2015 along with a requirement for specialist input.

“This is buttressing the PBS changes, and if anything, suggesting they should go further,” Professor Handelsman said.

“Management decisions should only be made after a systematic approach to the diagnosis of hypogonadism, seeking to distinguish between pathological and functional causes of a low serum testosterone level,” the guidelines state.

A diagnosis of pathological hypogonadism is based on at least two measurements of circulating testosterone, LH and FSH concentrations, which should be performed with mass spectrometry rather than immunoassay.

Healthy testosterone levels on mass spectrometry are 10.4-30.1 nmol/L in men 21 to 35 years with healthy reproductive function, and 7.4-28 nmol/L in unselected young men, the guidelines say.

Very healthy men aged 70 to 89 have a healthy range of 6.4-25.6 nmol/L.

Authors of the guidelines blame terms such as “late-onset hypogonadism” and “andropause” for promoting the idea that androgen-deficieny was a disease in itself.

But clinicians should disregard age as either an indication or contraindication, with serum testosterone levels declining on average up to 2% per year in healthy men, they wrote.

There had been a 100-fold increase in global testosterone prescribing over the last 30 years, and a six- to eightfold
increase in 20 years in Australia, Professor Handelsman said.

This has occurred without any new indications for testosterone treatment, and a lot of the new prescribing over the last two decades was likely “misguided”, he said.

However, the new Australian recommendations conflict with a June consensus statement from 17 international clinicians, which say that men with symptoms and signs of testosterone deficiency may benefit from treatment regardless of whether they had an identified underlying aetiology.

“We fail to see the logic of restricting treatment to those with identified causes, particularly since many symptomatic men may benefit without a known cause,” the consensus statement stated, likening it to treating hypertension without knowing the cause.

Dr Michael Lowy, GP and men’s health physician, said testosterone prescribing was a controversial topic, with each country having different guidance.

Australia had the “toughest” restrictions in the world, with other countries using around 8 nmol/L to 11 nmol/L as a trigger for treatment, he said.

He said doctors should try to adhere as closely as possible to the guidelines, but there may be instances to prescribe testosterone off-label.

“With careful consideration of the patient’s health and the issues associated with therapy, you might give them an off label, private prescription.

“But testosterone has to be almost regarded as insulin, in that it’s a lifelong treatment.”

The Australian guidelines classify testosterone prescribing for male infertility, sexual dysfunction or impotence, or non-specific symptoms such as lethargy, tiredness and low energy as “misuse”.

Prescribing androgens for sporting, recreational, cosmetic or occupational reasons classified as “abuse”.

Meanwhile the PBAC’s Drug Utilisation Sub Committee has prioritised a review into testosterone prescribing, only a year after the changes to the PBS listing.

MJA; online 15 August

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