Temporal trends in gender-affirming hormone therapy initiation: evidence from whole-of-population Australian administrative data.

A total of 32,241 individuals initiated gender-affirming hormone therapy in Australia between 2013 and 2024.

• 11,883 individuals initiated testosterone-based GAHT over the study period.
• 20,358 individuals initiated oestrogen-based GAHT over the study period.
• Data were derived from longitudinal national prescribing data (whole-of-population Australian administrative data).
• The study period spanned 12 years, from 2013 to 2024.

Annual GAHT initiation increased substantially over the study period, rising from 1,118 in 2013 to 5,135 in 2024.

• Initiation numbers in 2013 were 1,118 individuals.
• Initiation numbers in 2024 reached 5,135 individuals.
• This represents approximately a 4.6-fold increase over the 12-year period.
• The increase aligns with international trends of increasing demand for gender-affirming care.

The proportion of individuals initiating testosterone-based GAHT grew over time relative to oestrogen-based GAHT.

• A 'growing share' of initiators accessed testosterone-based GAHT over time.
• Over the full period, oestrogen-based initiators (20,358) outnumbered testosterone-based initiators (11,883).
• The shift in proportions toward testosterone-based GAHT reflects changing demographic patterns in those seeking gender-affirming care.

The mean age at GAHT initiation declined markedly from 50 years in 2013 to 26 years in 2024.

• Mean age at initiation was 50 years in 2013.
• Mean age at initiation fell to 26 years in 2024.
• This represents a 24-year decrease in mean age at initiation over the study period.
• The authors describe this as consistent with 'increasing demand among younger populations.'
• This trend aligns with international observations in gender-affirming care.

The findings highlight the need for specialised, accessible gender-affirming care and improved data collection in Australia.

• The authors note the results 'underscore the importance of improved data collection to inform health policy and clinical practice.'
• The study used whole-of-population administrative data, indicating a population-level analysis rather than a clinical cohort.
• The authors identify implications for health policy given increasing and younger demand for GAHT services.