Nason/clinicaltrials-database

ClinicalTrials.gov Database (AACT)

A clean, queryable DuckDB database built from the AACT flat files -- the most comprehensive structured export of ClinicalTrials.gov data.

59,028,978 rows across 48 tables covering every registered clinical trial.

Built with clinicaltrials-database.

Quick Start

DuckDB CLI

INSTALL httpfs;
LOAD httpfs;
ATTACH 'https://huggingface.co/datasets/Nason/clinicaltrials-database/resolve/main/clinicaltrials.duckdb' AS ct (READ_ONLY);

-- Trials by phase
SELECT overall_status, COUNT(*) as n
FROM ct.studies
GROUP BY overall_status
ORDER BY n DESC;

Python

import duckdb
con = duckdb.connect()
con.sql("INSTALL httpfs; LOAD httpfs;")
con.sql("""
    ATTACH 'https://huggingface.co/datasets/Nason/clinicaltrials-database/resolve/main/clinicaltrials.duckdb'
    AS ct (READ_ONLY)
""")
con.sql("SELECT * FROM ct.studies LIMIT 5").show()

DuckDB uses HTTP range requests, so only the pages needed for your query are downloaded.

Tables

Table	Description	Rows
reported_events	Summary of reported adverse events	12,034,973
outcome_measurements	Summary data for outcome measures by study group	4,995,195
browse_conditions	NLM-generated MeSH terms for study conditions	4,368,819
design_outcomes	Planned outcome measures and observations	3,761,914
facilities	Facility names, addresses, and recruiting status	3,523,526
baseline_measurements	Demographic and baseline measures by group	2,963,066
browse_interventions	NLM-generated MeSH terms for study interventions	2,553,067
result_groups	Aggregate list of group titles/descriptions for results reporting	2,217,791
keywords	Investigator-provided keywords describing the study	1,621,092
outcome_counts	Sample sizes for each outcome by study group	1,608,622
design_group_interventions	Cross-reference mapping design groups to interventions	1,344,197
study_references	Citations to publications related to the study	1,140,181
design_groups	Protocol-specified groups or cohorts assigned to interventions	1,108,587
conditions	Disease or condition names studied in each trial	1,083,005
interventions	Interventions or exposures: drugs, devices, procedures, vaccines	1,019,126
sponsors	Sponsor and collaborator names and types	960,579
milestones	Participant progress through each stage of the study	898,696
countries	Countries where the study has sites	816,098
id_information	Identifiers other than NCT ID (org study IDs, secondary IDs)	796,767
outcomes	Outcome measure descriptions and time frames	666,333
outcome_analysis_groups	Groups involved in each outcome analysis	631,153
reported_event_totals	Totals of reported adverse events by category	604,152
calculated_values	AACT-computed fields: months to report results, facilities count, etc.	602,514
studies	Core study record: title, status, phase, type, dates, enrollment, and regulatory info	602,514
drop_withdrawals	Summary of participant withdrawals: counts and reasons	602,414
brief_summaries	Brief text summary of the study protocol	601,530
detailed_descriptions	Detailed text description of the study protocol	601,530
eligibilities	Participant eligibility criteria (inclusion/exclusion, age, sex)	601,530
designs	Study design details: allocation, masking, assignment, purpose	597,720
responsible_parties	Parties responsible for submitting study information	584,077
overall_officials	People responsible for overall scientific leadership	534,026
search_term_results		513,966
intervention_other_names	Synonymous names for interventions	486,506
facility_contacts	Contact information at each study facility	421,325
outcome_analyses	Statistical analyses performed on outcomes	326,441
baseline_counts	Sample sizes at baseline for each study group	240,449
facility_investigators	Investigator names at each study facility	226,624
central_contacts	Primary and backup contacts for enrollment questions	226,221
ipd_information_types	Individual participant data sharing information types	96,041
provided_documents	Protocol, SAP, and informed consent form documents	85,636
result_contacts	Points of contact for scientific information about results	80,079
result_agreements	Agreements between sponsor and principal investigators about results	80,079
participant_flows	Recruitment and pre-assignment details	80,079
links	Web links relevant to the study	75,845
pending_results	Events related to submission of results for QC review	33,534
documents	Full study protocol and statistical analysis plan	10,838
retractions	Retraction notices for study results or publications	335
search_terms		186

Data Source

AACT (Aggregate Analysis of ClinicalTrials.gov) -- maintained by the Clinical Trials Transformation Initiative (CTTI). Updated daily from ClinicalTrials.gov. This is public domain U.S. government data.

License

Database build code: MIT. Underlying data: public domain (U.S. government work).

GitHub

Full source code, build instructions, and data dictionary: github.com/ian-nason/clinicaltrials-database

Changelog

2026-09-14 — Data refresh (AACT snapshot 2026-09-14)

• Rebuilt from the AACT flat-file export dated 2026-09-14. Total rows 58,046,170 → 59,028,978 across 48 tables; studies 592,206 → 602,514.
• AACT moved its download page (/pipe_files → /downloads, with a site-relative "Download File" link); the builder now finds the export there and still accepts the old layout.
• Fix: the header-only search_results file recreated an empty phantom table (removed by hand in July). The builder now drops every zero-row table, and validate_database.py fails if search_results exists or if any of the seven studies.*_date_type columns is not VARCHAR with ACTUAL/ESTIMATED.
• DuckDB memory capped at 6 GB with 4 threads (overridable via DATAPOND_MEMORY_LIMIT / DATAPOND_THREADS); publish_to_hf.py --card-only.

2026-07-06 — Full refresh + data-quality audit

Rebuilt from the AACT snapshot of 2026-07-04 and repaired after an independent SQL-verified audit.

Data changes

• 58,046,170 rows across 48 tables; 592,206 studies (through June 2026).

Fixes

• All seven studies.*_date_type columns restored: they hold ACTUAL/ESTIMATED strings and had been silently nulled by date casting. Anticipated-vs-actual analyses (reporting timeliness, FDAAA compliance) are possible again.
• README example queries corrected: categorical values are AACT's UPPER_SNAKE ('COMPLETED', 'PHASE3', 'DRUG'); the phantom has_results column replaced with calculated_values.were_results_reported.
• Phantom search_results table removed from metadata and the dictionary (its source file is header-only and never loads).

Known caveats (see README for the full list)

• Results are posted for only ~24% of completed interventional trials.
• No reliable registration time series before 2005 (ICMJE mandate cliff).
• The final snapshot month is right-censored; truncate trends at May 2026.
• Free text uses ~ as a newline surrogate.