Inclusion of special populations in clinical research: important considerations and guidelines

BACKGROUND: Trials that involve human participants call for experiments or observations that are performed in a clinical research setting. Currently, there are over 16,000 clinical trials open in the United States. Despite continuing efforts to include "special populations" in clinical trials, there are gaps in participation for people who are either minors or elderly adults, are from historically under-represented minorities, or live in rural communities. The inclusion of these special populations in clinical trials research is essential for conclusions that benefit all populations. Data suggest that study partic-ipation rates for special populations have fallen to levels that could endanger the successful performance of some types of research. This is particularly concerning in the 21st century, where demographic trends in the United States continue to shift towards an older and Hispanic population with fewer rural dwellers. Trends in New Mexico and other minority-majority states mirror many of these shifts. RELEVANCE FOR PATIENTS: In this review, we highlight improvement strategies for enhanced clinical trial participation by members of special populations. Key drivers for disparate clinical trials participation and outcomes often include differences in genetics, physiology, and perceptions of mistrust towards researchers. To overcome these barriers, we focus on best practices in recruitment strategies from the perspectives of the participants, the researchers and the institutions that support clinical trials.