A systematic review of ethnic diversity in clinical trial participation in Aotearoa

Diverse ethnic representation in clinical trials is critical to ensuring research priorities align with patient need and uphold commitments to health equity. In Aotearoa New Zealand, this is crucial given the persistent health inequities faced by Māori despite obligations of the government to Te Tiriti o Waitangi/the Treaty of Waitangi. We report the findings of a systematic review of ethnic representation, with a focus on Māori and Pacific peoples, in randomised controlled trials (RCTs) undertaken in New Zealand between 2010 and 2020.

A search was undertaken for RCTs undertaken in New Zealand between 2010 and 2020, registered in the Australia New Zealand Clinical Trials Registry (ANZCTR) and published in a peer-reviewed journal. Ethnicity data were categorised to Stats NZ Tatauranga Aotearoa (Stats NZ) level one or two codes. The Preferred Reporting Items for Systematic reviews and Meta-Analyses guideline was followed. The primary outcome was the proportion of each Stats NZ level one ethnicity code, for all participants recruited to RCTs conducted in New Zealand which reported ethnicity.

One thousand and forty trials were identified, 342 met the inclusion criteria, of which 103 reported no ethnicity data. For 295,254 participants across all 239 included studies, 6.1% of participants were European, 2.9% Māori, 1.4% Pacific peoples, 7.5% Asian, 2.5% Middle Eastern/Latin American/African (MELAA) and 9.0% Other ethnicity, with 70.6% Residual (unable to be categorised).

Ethnicity reporting in New Zealand-based clinical trials is inadequate and not standardised. Mandatory ethnicity reporting per Stats NZ codes to the New Zealand Health and Disability Ethics Committees, ANZCTR and peer-reviewed journals, should be considered mandatory for RCTs undertaken in New Zealand.