CT.gov Condition Enrollment Gap

Paper

Which condition families most often leave older CT.gov study pages without actual enrollment, obscuring realized sample size after study closure? We analysed 249,507 eligible older closed interventional studies from the March 29, 2026 full-registry snapshot using one condition-family label per study. We defined an enrollment gap as missing actual enrollment among older closed studies, then ranked large condition families by stock and rate. Oncology led the stock table at 2,765 studies, followed by the broad OTHER bucket at 1,815, Cardiovascular at 1,179, and Infectious disease at 747. Oncology also had the highest large-family enrollment-gap rate at 6.5 percent, ahead of cardiovascular at 4.5 percent and gastrointestinal and hepatic at 4.5 percent. Condition-family enrollment gaps show that realized sample-size discipline is weakest in exactly the therapeutic areas that dominate much of the older CT.gov registry stock. Condition families are keyword-derived registry groupings, so they approximate therapeutic portfolios rather than formal disease ontologies or mutually exclusive diagnoses alone.