CT.gov Condition Primary-Only Gap

Paper

Which condition families most often leave older CT.gov study pages without the primary outcome description while keeping the broader detailed-description field? 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 a primary-only gap as missing primary outcome description with detailed description still present, then ranked large condition families by stock and rate. Oncology led the condition-family primary-only-gap stock table at 7,102 studies, followed by Other at 5,818, Cardiovascular at 3,766, and Infectious disease at 2,584. Oncology also had the highest large-family primary-only-gap rate at 16.8 percent, ahead of Cardiovascular at 14.5 percent and Infectious disease at 14.3 percent. Condition-family primary-only gaps show where the endpoint sentence disappears most often even though the broader study narrative remains on the page. Condition families are keyword-derived registry groupings rather than formal disease ontologies or mutually exclusive diagnoses across all studies. They simplify diagnoses for readers.