Identification of clinical trials (CTs) conducted in Spain (1971-1995)

Article type
Authors
Bonfill X, Marti J, Garcia F
Abstract
Objective: To find and describe all clinical trials (CTs) and randomized clinical trials (RCTs) conducted in Spain, published and unpublished, from 1971 to 1995. It is hoped that this information will improve understanding of this activity in our country, evaluate the exhaustively of different registries and facilitate the Cochrane Collaboration reviews.

Methods: Descriptive field study. Manual and electronic location of CTs. The following information sources were used: 1. hand searching of all publications in Spanish journals in 1971-1995; 2. electronic databases (Medline, Embase, and IME (Spanish Index Medicus); 3. the Spanish CT Database in the Ministry of Health Pharmacy Department (1983-1995), with clinical trials submitted for administrative approval; 4. contacts with all Clinical Research Ethics Committees, Research Committees, Research Units, and research financing agencies, Pharmacy and Clinical Pharmacology Departments; 5. contacts with pharmaceutical companies and similar industries in Spain. 6. the TESEO database, which contains the doctoral theses from Spanish Universities. The field work was developed by 3 contracted reviewers and several previously trained volunteers.

Results: The data currently available (April 1997) comes from the manual search source. A total of 1402 possible CTs have been identified, of which 890 (63.5%) have been reviewed. Of these, a total of 387 (43.5%) CTs were identified, whereas 503 (56.5%) were rejected because they did not fulfil the inclusion criteria. In all, 336 (87.%) of the 387 were published in journals indexed by the IME.

Discussion: Our manual search strategy prioritized sensitivity in the first stage, followed by a final, more specific approach. A high percentage of identified CTs would not have been located without manual journal searches. The planned linkage of all sources of information will make it possible to quantify and analyze publication bias in Spain and assure exhaustive detection of most CTs developed in this country.