Screen failures in clinical trials in retina

Purpose Disparities in clinical trials are a major problem due to significant underrepresentation of certain gender, racial and ethnic groups. Several factors including stringent eligibility criteria and recruitment strategies hinder our understanding of retinal disease. Thus, we aimed to study the various reasons of screen failures and specific patient and study characteristics among screen failures. Design This is a cross-sectional retrospective study Methods Screening data of 87 trials from 6 centers were analyzed. Study characteristics (disease studied, phase of trial, route of drug administration) and patient demographics (age, gender, race, ethnicity, and employment status) were compared among different causes of screen failures. Screen failures were broadly classified into six categories: exclusion due to vision-based criteria, exclusion due to imaging findings, exclusion due to other factors, patient-related criteria, physician related criteria and miscellaneous. Descriptive statistics, Pearson Chi-square test and ANOVA were used for statistical analysis. Main outcome measures Determine the prevalence of various reasons for screen failures in multiple trials and its trend among different study and patient characteristics. Results Among 87 trials and 962 patients, 465(48.2%) patients were successfully randomized and 497(51.8%) patients were classified as screen failures. The trials were conducted for various retinal diseases. Mean age was 76.50 ±10.45 years and 59.4% were females. Predominantly whites(93.4%) and unemployed/retired patients(66.6%) were screened. Of the 497 screen failures, most were due to patients not meeting inclusion criteria of imaging findings (n=221[44.5%]) followed by inclusion of vision-based criteria (n=73 [14.7%]), exclusion due to other factors (n=75[15.1%]), patient-related (n=34[6.8%]), physician-related (n=28[5.6%]) and miscellaneous reasons (n= 39[17.8%]). Reason for screen failure was not available for 27(5.4%) patients. A higher proportion of patients screened for surgical trials (15%) declined to participate in the study compared to non-invasive trials involving topical drugs and photobiomodulation (0%).(p=0.02) Conclusion Patients not meeting the imaging and vision-cased criteria were the most common reasons for screen failures. Whites and unemployed patients predominantly participated in clinical trials. Patients are more inclined to continue participation in non-invasive clinical trials compared to surgical trials. Better recruitment strategies and careful consideration of study criteria can aid in decreasing the rate of screen failures.