(PP1412) Diversity in U.S.-Based Randomized Control Trials of Tinnitus: A Systematic Review

Inclusion of diverse research participants is crucial for enhancing hearing health equity. We performed a comprehensive and systematic literature search via PubMed, Web of Science, Clinical-Trials.gov, and the Cochrane Central Register of Controlled Trials (CENTRAL). Our goal was to identify prospective, randomized clinical trials (RCTs) of tinnitus intervention conducted in the United States (US) from January 1994 to September 2021 and published in peer-reviewed journals. Thirty-two articles met all inclusion criteria and were further analyzed. Clinical and public health implications of the results of this study will be discussed considering the existing literature. 

Summary: 

Rationale &

Purpose: The 2020 United States (US) Census data reveal that more than one-third of the US population identifies itself as a racial/ethnic minority and more than 50% of the population identifies itself as female (US Census Bureau, Retrieved from: https://www.census.gov/quickfacts/fact/table/US/LFE046219). Hence, it is logical to invest resources in participant inclusivity in clinical research.

Research indicates that people of different genders, races, and socio-economic sections of the society can have different prevalence rates, hearing loss/tinnitus experiences and treatment outcomes. Basso et al. (2020) found that of the 7,615 individuals with tinnitus they surveyed, the prevalence of generalized anxiety syndrome was 1.6 times higher in females than in males. Similarly, while African Americans are less likely to experience negative effects of noise induced hearing loss, they might be at a greater risk for ototoxicity because of increased endocochlear melanocytes (Barr-Hamilton et al., 1991; Sun et al., 2014). Hence, race can affect hearing loss and resultant tinnitus in multi-factorial ways. Lastly, studies have demonstrated relationships between participants’ level of education and employment (variables associated with socio-economic status) with tinnitus severity (Hoekstra et al., 2014; Holgers et al., 2005). Overall, a review of the literature indicates that various demographic factors (gender, race/ethnicity, and socio-economic factors) can impact tinnitus perception and management.

Randomized controlled trial (RCT) is a rigorous research design utilized to assess treatment effectiveness of disorders like tinnitus. An accurate representation of participants in RCT studies ensures greater reliability of generalization in the larger population (Hariton & Locascio, 2018).

The purpose of this study was to investigate if peer-reviewed randomized controlled trials (RCTs) for the management/treatment of tinnitus conducted in the United States (US) include diverse participants in terms of gender, race/ethnicity, education, occupation, and income.

Methods: We performed a comprehensive and systematic literature search via PubMed, Web of Science, Clinical-Trials.gov, and the Cochrane Central Register of Controlled Trials (CENTRAL). Our goal was to identify prospective, RCTs of tinnitus intervention conducted in the US from January 1994 to September 2021 and published in peer-reviewed journals.

Results: A total of 2584 studies were retrieved. Thirty-two peer-reviewed articles met all inclusion criteria. Of the included studies, approximately 96% reported participants’ gender. Approximately 15% studies reported race/ethnicity information in alignment with the US Census Bureau. However, an underrepresentation of both females and people of color was evident across studies. Reporting of socio-economic status information of participants was also scarce, with only 25% studies reporting education and/or occupation of participants and 0% reporting income levels.

Conclusion: This study indicates under-representation and under-reporting of diverse participant pools in tinnitus research. Participation in clinical trials offers opportunities for better health outcomes and therefore, researchers can help make a positive change in society for everyone with an inclusive research model (Majumdar et al., 2008). Sustainable strategies for including diverse research participants are essential for hearing healthcare equity. Research and strategies to promote this goal will be discussed.