Paper
Oncology and OTHER dominate condition-family stock, but Healthy volunteers are much harsher on rate than the major named disease portfolios.
Which condition families most often leave older CT.gov study pages without primary outcome descriptions, obscuring the main endpoint for readers? 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-outcome gap as a missing primary outcome description, then ranked large condition families by stock and rate. Oncology led the condition-family primary-outcome-gap stock table at 11,207 studies, followed by the broad OTHER bucket at 10,942, Cardiovascular at 7,006, and Metabolic at 5,006. Healthy volunteers had the sharpest large-family primary-outcome-gap rate at 35.0 percent, ahead of Metabolic at 28.9 percent and Renal and urology at 28.8 percent. Condition-family primary-outcome gaps show where registry pages omit the endpoint-defining sentence in major therapeutic areas, not only smaller fringe portfolios. Condition families are keyword-derived registry groupings rather than formal disease ontologies or mutually exclusive diagnoses across all studies. They simplify diverse diagnoses into usable public buckets.