Incidence and baseline predictors of discontinuation in DRCRnet studies.

OBJECTIVE

To evaluate the incidence and baseline predictors of participant discontinuation in Diabetic Retinopathy Clinical Research Retina Network (DRCRnet) studies

METHODS

Using the publicly available DRCRnet data, discontinuation rate and its 95% confidence intervals (95% CI) were calculated. Univariable and multivariable logistic regression models were used to assess predictors for participant discontinuation, including demographic, clinical, and study design characteristics, and within-study correlation was accounted for using generalised estimating equations.

RESULTS

Among 7353 participants (mean age 60 years, 48.0% female, 64.1% non-Hispanic (NH)-White, 17.8% NH-Black, 14.2% Hispanic), 1110 participants (15.1%, 95% CI 14.3-15.9%) discontinued study participation over a median 24-month follow-up. Multivariable analysis showed significantly higher risk of discontinuation among Hispanic (aOR 1.73, 95% CI 1.38-2.18) and NH-Black (aOR 1.36, 95% CI 1.14-1.62) participants, those with age <50 years (aOR 1.46, 95% CI 1.21-1.77), 50-59 years (aOR 1.26, 95% CI 1.05-1.51), or ≥70 years (aOR 1.20, 95% CI 1.03-1.39), participants with higher baseline HbA1c (aOR 1.09 per unit increase, 95% CI 1.06-1.12), or baseline blood pressure ≥140/90 mmHg (aOR 1.24, 95% CI 1.09-1.41), and those in studies with follow-up length 24 to <36 months (aOR 1.64, 95% CI 1.02-2.64) or 36 to 48 months (aOR 2.68, 95% CI 1.87-3.84).

CONCLUSIONS

Approximately 15% of participants in the eligible DRCRnet studies discontinued participation. Racial and ethnic identity, age, glycaemic and blood pressure control, and study follow-up duration are significant predictors of participant discontinuation and should be considered when designing future studies.