Impact of limited language proficiency on participation in venous thromboembolism research: a retrospective analysis

Background: Limited language proficiency is an established barrier to research participation among racialized populations. While prior studies have highlighted the underrepresentation of racialized populations in venous thromboembolism (VTE) research, the impact of limited language proficiency as a reason for nonconsent among eligible patients is unknown.

Objectives: To determine the impact of language barrier as the primary reason for VTE research non-participation.

Methods: We reviewed all prospective VTE studies conducted at a research-intensive academic thrombosis research program in Canada between 2014 and 2024. Studies with screening logs that systematically and consecutively captured eligibility assessment and reasons for nonconsent were included. Primary outcome was nonconsent of a screen-eligible patient due to limited language proficiency as the reported reason. We derived pooled estimates of nonconsent due to limited language proficiency as a proportion of consented participants and determined subgroup rates by phase of VTE management, associated medical conditions, and recruitment settings.

Results: Screening logs of 28 studies with 22 057 screening events, 8317 screen-eligible patients, and 3320 consented participants were included. For every 100 consented participants, 3.2 (95% CI, 2.0-5.3) screen-eligible individuals were unable to provide consent due to limited language proficiency. Rates of nonconsent were highest in studies involving cancer (5.6 per 100 participants; 95% CI, 2.9-10.4) and in studies recruiting patients from ambulatory settings outside of the thrombosis clinic (10.8 per 100 participants; 95% CI, 4.8-22.6).

Conclusion: Language proficiency is a key barrier to VTE research participation. Urgent implementation of targeted interventions aimed at mitigating linguistic barriers is essential to ensure equitable opportunities for VTE research participation for racialized patients disproportionately affected by language proficiency.