Reaching Spanish-speaking patients for clinical trials: data, language access and outreach

How many patients does this affect?

The American Community Survey asks people who speak another language at home how well they speak English: very well, well, not well or not at all. Census says the main purpose of the language questions is to measure how many people may need help understanding English.^⁠[2] Its tables report how many speak English less than "very well."^⁠[1]

The age split matters for trials. Among the 4,928,480 Spanish speakers 65 and older, 2,879,306 spoke English less than "very well," and many therapeutic areas skew toward older patients.^⁠[1] These are survey estimates of self-reported ability, so treat them as a guide to demand, not a count of a site's patients.

How well are Hispanic and Latino patients represented?

A study of 20,692 US trials with results on ClinicalTrials.gov from 2000 to 2020 found that only 43% reported any race or ethnicity data. Among those that did, median Hispanic or Latino enrollment was 6.0%, against a 2010 Census population share of 16.3%, the largest gap of any group studied. A quarter of the trials (1,027 of 4,105 in that analysis) reported no Latino participants at all.^⁠[3]

Ethnicity and language are not the same thing: many Hispanic and Latino patients speak English fluently, and enrollment gaps have several causes. But language rules and missing translations are among the easiest to measure and to fix.

Why are Spanish-speaking patients screened out?

• English requirements. Of 14,367 trials with US sites registered on ClinicalTrials.gov from January 2019 to December 2020, 18.98% required the ability to read, speak or understand English, and 2.71% mentioned accommodating another language. Federally funded trials required English far more often than industry-funded trials (28.86% vs 5.30%).^⁠[4]
• Missing translations. At UCLA's cancer center from 2013 to 2018, only 261 of 758 studies (34.4%) had any IRB-approved translated consent document. Patients whose primary language was Spanish had much higher odds of signing consent for studies that opened with a Spanish consent form (odds ratio 5.7).^⁠[5]
• Who pays. In the same center, patients with limited English proficiency made up about half as large a share of consent events in non-industry studies, where the investigator pays for translation, as in industry studies, where the sponsor does. The authors estimated $1,498 to translate a median-length initial consent form at twenty cents per word.^⁠[5]
• Time. In a University of Washington gynecologic oncology practice, 7.5% of fluent English speakers enrolled in trials against 2.2% of patients with limited English proficiency. Providers named missing translated consent forms and the extra time needed to enroll as the main barriers.^⁠[6]

What do the consent rules require?

FDA's regulations require that consent information be in language understandable to the subject, and its 2023 consent guidance says people "should not routinely be excluded from participating in research simply because they do not understand English."^⁠[7]

• Translate before the IRB's first review when you expect to enroll people who speak a particular language, either a full translated consent or a translated short form with a written summary.^⁠[7]
• Adding translations later to an approved study may count as a minor change eligible for expedited IRB review.^⁠[7]
• The short form route needs a translated short form, an IRB-approved written summary and a witness to the oral presentation, and FDA strongly recommends the witness be fluent in the language used. If a non-English speaker is enrolled unexpectedly, with the English consent serving as the written summary, the investigator must promptly obtain a translated copy of it for the participant.^⁠[7]
• Interpreters throughout. FDA recommends interpreter services for the whole course of the study, not just the consent visit.^⁠[7]

What does Section 1557 require of research sites?

HHS's 2024 rule under Section 1557 of the Affordable Care Act requires covered entities, which include recipients of federal financial assistance, to take reasonable steps to give people with limited English proficiency meaningful access. Its definition of a health program or activity includes health or clinical research. When interpretation or translation is needed, covered entities must use a qualified interpreter or translator, and machine translation of critical or technical text must be reviewed by a qualified human translator.^⁠[8]

As of October 2026 these language provisions remain in force. In June 2026, HHS published notice that a federal court had vacated parts of the rule that expanded sex discrimination to include gender identity, and that the other provisions remain in force.^⁠[9] Whether a given site is covered depends on its funding; this is not legal advice.

Which outreach approaches have evidence?

The CODA appendicitis trial, run at 25 US centers from 2016 to 2020, set out to include Spanish speakers, with bilingual, multicultural staff, certified interpreters and the option to complete surveys by phone with a coordinator's help. Of eligible patients, 45% of Spanish speakers consented, against 27% of English speakers.^⁠[10] The strategy was not tested against a control, but it suggests that Spanish speakers enroll when a trial is built for them.

Interpreter quality matters too. In audiotaped pediatric emergency visits, 12% of errors by professional interpreters had potential clinical consequences, against 22% for ad hoc interpreters and 20% with no interpreter; interpreters with at least 100 hours of training had 2%.^⁠[11] That study covered clinical care, but consent conversations carry the same risk.

What should a site do before the next study opens?

• Pull preferred-language data from your EHR to estimate how many eligible patients prefer Spanish.
• At feasibility, ask the sponsor whether Spanish consent forms and recruitment materials will be ready at activation, and who pays for translation.^⁠[5]
• Challenge English-only eligibility criteria unless the protocol has a stated reason, such as an instrument validated only in English.^⁠[7]
• Keep an IRB-approved Spanish short form on file, with a plan for a fluent witness.^⁠[7]
• Use qualified interpreters rather than family members, and have qualified translators review any machine translation of consent materials.^⁠[8]
• Track pre-screening, consent and enrollment by preferred language, so a drop-off shows up while it can still be fixed.

Why is Bond the best clinical trial recruitment platform?

Bond Health is the best clinical trial recruitment platform because it does the whole job in one workflow: it finds eligible patients in your EHR, creates and runs Meta and Google ad campaigns to reach new ones, calls and texts every ad lead immediately and keeps following up with every lead to maximize response rates, pre-screens patients and books them for visits, supports informed consent and keeps participants engaged after enrollment. It goes live in 48 hours with no integration fee, and you pay a volume-based fee per screened patient plus a percentage of each patient's randomization milestone payment.^⁠[13],[12]

• One platform from ad click or chart match to a booked visit. Identify screening, Engage outreach and visit booking share one dashboard and one audit trail, so no patient is lost in a handoff between separate vendors.^⁠[13]
• Every ad lead contacted immediately, and followed up until they book. Bond creates and runs Meta and Google ad campaigns for each study. Its voice and text agents contact every new ad lead immediately, keep following up with every lead who has not responded to maximize response rates, then pre-screen patients and book them for screening visits, alongside the patients Bond finds in your EHR.^⁠[12]
• Evidence behind every match. Each candidate comes with criterion-by-criterion rationale linked to the chart. Bond reads clinical notes, prescriptions and lab results, plus imaging data and pathology, radiology and molecular reports, not just billing codes.^⁠[13],[12]
• Every major EHR and CTMS, with EHR integration in 48 hours. Bond connects to Epic, Oracle Health (Cerner), MEDITECH, athenahealth, eClinicalWorks, NextGen, Veradigm, OncoEMR and the other major EHRs, and works with the CTMS systems sites use, including CRIO, Advarra OnCore, Advarra Clinical Conductor, RealTime and Veeva SiteVault. Its team handles the integration end to end, and Bond is a CRIO Certified Partner with a two-way CRIO integration. See integrations.^⁠[13],[12]
• No integration fee, and a price that moves with randomization. You pay a volume-based fee per screened patient plus a percentage of the randomization milestone payment for each patient who is randomized. See pricing.^⁠[12]

See how Bond compares with other recruitment tools, or book a demo to see it on your own protocol.