Abstract 16854: Successful Retention of Vulnerable Populations in New York City: The BETTER-BP Randomized Trial

Introduction: Clinical trial retention in safety-net practices is challenging. To better understand reasons for loss to follow-up, we analyzed data from an ongoing clinical trial in the NYC public hospital system.

Methods: We analyzed the first 185 participants enrolled in the BETTER-BP study, an ongoing randomized trial of wireless antihypertensive medication adherence monitoring with a financial incentive lottery to promote medication taking behavior. BETTER-BP enrolls participants from two NYC public hospitals (Bellevue and Gouverneur) and follow-up lasts 12 months. We reported the rate of loss to follow-up at 12 months and assessed baseline characteristics (age, sex, race, ethnicity, insurance status, BMI, blood pressure, comorbidities, and substance use) of those lost vs. retained. ANOVA was used for continuous variables, and the Chi-squared test for categorical variables.

Results: Median age was 55.0 (47.5, 62.5) years, 59% were female, 59% Hispanic, and 26% Non-Hispanic Black. Three quarters were Medicaid-insured or uninsured. There were 155 participants retained at 12 months (83.8% retention rate). Characteristics of those retained vs. lost to follow-up are shown in the Table. Participants who were lost to follow-up were more likely to report current alcohol use (43.3% vs. 36.8%, p < 0.001) and illicit substance use (16.7% vs. 3.9%, p < 0.001). Notably, missingness in alcohol use and illicit substance use was also higher among those lost to follow up. Other baseline characteristics were similar between the two groups.

Conclusion: Overall retention was high (>80%). Alcohol and illicit drug use were associated with loss to follow up and may serve as markers for future strategies to mitigate attrition.