Relationship Between Social Vulnerability Indicators and Trial Participant Attrition: Findings From the HYVALUE Trial

Abstract

Background: Social vulnerability indicators are associated with health care inequities and may similarly impede ongoing participation in research studies. We evaluated the association of social vulnerability indicators and research participant attrition in a trial focused on reducing health disparities.

Methods: Self-identified White or Black adults enrolled in the HYVALUE trial (Hypertension and VALUEs), a randomized trial testing a values-affirmation intervention on medication adherence, from February 2017 to September 2019 were included. The self-reported measures of social vulnerability indicators included: (1) Black race; (2) female gender; (3) no health insurance; (4) unemployment; (5) a high school diploma or less; and (6) financial-resource strain. Full attrition was defined as not completing at least one 3- or 6-month follow-up study visit. Log-binomial regression models adjusted for age, gender, race, medical comorbidities, and the other social vulnerability indicators to estimate the relative risk of each social vulnerability indicator with study attrition.

Results: Among 825 participants, the mean age was 63.3 years (±11.7 years), 60% were women, 54% were Black, and 97% reported at least one social vulnerability. Overall, 21% participants had full attrition after study enrollment. After adjustment for all other social vulnerabilities, only financial-resource strain remained consistently associated with full attrition (relative risk, 1.71 [95% CI, 1.28-2.29]). In a secondary analysis of partial attrition (completed only one follow-up visit), financial-resource strain (relative risk, 1.40 [95% CI, 1.09-1.81]) and being uninsured (relative risk, 1.54 [95% CI, 1.01-2.34]) were associated with partial attrition.

Conclusions: In a trial aimed at reducing disparities in medication adherence, participants who reported financial-resource strain had a higher risk of participant attrition independent of race or gender. Our findings suggest that efforts to retain diverse populations in clinical trials should extend beyond race and gender to consider other social vulnerability indicators.

Registration: URL: https://www.

Clinicaltrials: gov; Unique identifier: NCT03028597.

Keywords: health care disparities; hypertension; minority groups; morbidity; social vulnerability.

Figures

Figure 1.

Unadjusted and adjusted risk ratios of social vulnerabilities with full attrition. Log binomial regression models compared participants with full attrition to those with partial attrition or no attrition. *Financial-resource strain was determined by participants’ self-reported level of difficulty paying for very basics like food, housing, medical care, and heating within the 3 months prior to enrolling into the trial. Participants who reported paying for basics was ‘somewhat hard’ or ‘very hard’ were categorized as having financial-resource strain. †The adjusted log-binomial models controlled for other social vulnerable indicators and the number of participant medical co-morbidities.

Figure 2.

Unadjusted and adjusted risk ratios of social vulnerabilities with partial attrition. Log binomial regression models compared participants with partial attrition (attended at least one study visit) to participants with no attrition. *Financial-resource strain was determined by participants’ self-reported level of difficulty paying for very basics like food, housing, medical care, and heating within the 3 months prior to enrolling into the trial. Participants who reported paying for basics was ‘somewhat hard’ or ‘very hard’ were categorized as having financial-resource strain. †The adjusted log-binomial models controlled for other social vulnerability indicators and the number of participant medical co-morbidities.

Figure 3.

Unadjusted and adjusted risk ratios of social vulnerabilities for full attrition versus no attrition. Log binomial regression models compared participants with full attrition to participants with no attrition. *Financial-resource strain was determined by participants’ self-reported level of difficulty paying for very basics like food, housing, medical care, and heating within the 3 months prior to enrolling into the trial. Participants who reported paying for basics was ‘somewhat hard’ or ‘very hard’ were categorized as having financial-resource strain. †The adjusted log-binomial models controlled for vulnerable social indicators and the number of participant medical co-morbidities.