Ethnic representation in randomised clinical trials is key to ensuring that the results of pharmacological treatments for mental disorders are applicable to the entire population. This representation is essential to ensure that we can trust the results of the studies and, therefore, the efficacy of the different treatments. Now, a study published in the journal JAMA Psychiatry reveals that fewer than half of mental health trials include information about participants' ethnicity. This is the first study to systematically analyse this aspect. One of the main authors is Joaquim Raduà, head of the Imaging of Mood- and Anxiety-Related Disorders (IMARD) group at IDIBAPS.
The study consisted of a review and meta-analysis of 1,683 clinical trials published between 1958 and 2023, with data from more than 375,000 participants. The results show that only 39.2% of clinical trials report on the ethnicity of the individuals included. Furthermore, this percentage varies significantly depending on the geographical region: while in the United States 58.7% of studies report this information, in Asia and the Middle East the percentage drops to 12.4% and in Central and South America, to just 8.7%.
“These differences could be partly due to the fact that more ethnically homogeneous cultures tend to pay less attention to the recording of ethnicity. But in today's world there is usually greater ethnic diversity than in the past. It would be advisable to have international guides that facilitate the recording and respectful description of the ethnicities of the study participants", Raduà highlights.
The authors also compared ethnic representation in clinical trials conducted in the United States with census data from that country. It was observed that, depending on the ages of the participants, some ethnicities have gone from being underrepresented to overrepresented, while others remain underrepresented.
For Joaquim Raduà, the lack of information and ethnic representation is not only a matter of transparency, but can have a real impact on the quality of scientific evidence on the efficacy of treatments, and, therefore, on clinical practice. And he adds: "I would like to emphasise that it is important to analyse the data by separating them according to the ages of the participants and the years of the studies, since if we mix everything up we could draw wrong conclusions."
