Demographic diversity of participants in clinical trials conducted in Singapore

The under-representativeness of participants in clinical trials limits the generalisability of results. This review evaluates the representative-ness within pharmaceutical randomised controlled trials (RCTs) in Singapore.

Four bibliographic databases were searched for papers on pharmaceutical RCTs which included Singapore adults (≥18 years old), published between 2017 and 2022. The demographic characteristics of study participants were compared against the population in the 2020 Singapore census. Recruitment strategies and authors' comments on the generalisa-bility of their findings were reviewed.

Thirty-three publications were included (19 Singapore-only studies and 14 multiregional trials which included Singapore). Where data were available, we found that females and Indians were under-represented compared to the census (41.3% versus [vs] 51.1%, P<0.05; 7.3% vs 9.0%, P<0.05). Ethnic diversity varied between individual studies, and almost half (46.2%) of Singapore-only studies achieved census levels. However, more than one-third of the trials provided no data (31.6%) or partial data (5.3%) on ethnicity. Half of the multiregional publications stated the number of participants recruited from Singapore, but only 1 reported any detail beyond Asian participants. Recruitment strategies were mentioned in fewer than half (42.4%), and less than a quarter (24.2%) commented on sample representative-ness or the external validity of the evidence generated.

There is room for improvement regarding the recruitment of RCT participants in Singapore, with particular attention to female gender and Indian ethnicity. Demographic data should also be presented in full. RCTs should be designed and reported such that clinicians can ascertain the generalisability to the Singapore population and the potential benefits from the studied interventions in clinical practice.