CT.gov Disease Geography Gap

Paper

How does geography reshape the hiddenness of major disease families once older CT.gov studies are grouped into U.S.-only, mixed, non-U.S., and no-country buckets? We analysed 249,507 eligible older closed interventional studies from the March 29, 2026 full-registry snapshot and linked geography buckets to oncology, cardiovascular, and metabolic families. The project compares two-year no-results rates, ghost-protocol rates, visible shares, and hiddenness scores across geography buckets within each selected disease family. U.S.-plus-non-U.S. studies were the cleanest geography bucket in every disease family: 29.9 percent no results in cardiovascular, 29.4 percent in metabolic, and 39.4 percent in oncology. No-U.S. studies were worst: 89.9 percent no results in cardiovascular, 90.3 percent in metabolic, and 86.8 percent in oncology. The disease story therefore depends on geography structure, because the same clinical area can move from moderately visible to deeply hidden depending on where studies are located. Geography buckets use recorded locations rather than verified recruitment shares, sponsor domicile, or disease-burden denominators.